Crashes in android
Hello! I successfully built godot-nim-stub for android (my fork: https://github.com/DrMoriarty/godot-nim-stub)
It starts and shows correct fps counter. But it crashes when I pressed the main scene. I added some debug output in https://github.com/DrMoriarty/godot-nim-stub/blob/master/src/mainpanel.nim
so log is:
```
06-27 00:22:28.057: D/GODOT(632): ** GODOT ACTIVITY CREATED HERE ***
06-27 00:22:28.077: D/AccessibilityManager(632): current package=org.godotengine.godotnimstub, accessibility manager mIsFinalEnabled=false, mOptimizeEnabled=true, mIsUiAutomationEnabled=false, mIsInterestedPackage=false
06-27 00:22:28.398: D/GODOT(632): command_line is null? no
06-27 00:22:28.447: I/godot(632): **INIT EVENT! - 0xf3e19310
06-27 00:22:28.447: I/godot(632): ***************** HELLO FROM JNI!!!!!!!!
06-27 00:22:28.447: I/godot(632): *******CLASS FOUND!!!
06-27 00:22:28.447: I/godot(632): STEP2, 0x10096e
06-27 00:22:28.447: I/godot(632): STEP3 -410202076
06-27 00:22:28.447: I/godot(632): STEP4, 0x20001d
06-27 00:22:28.447: I/godot(632): STEP4.5, 0x100972
06-27 00:22:28.448: I/godot(632): STEP7
06-27 00:22:28.448: I/godot(632): STEP8
06-27 00:22:28.448: I/godot(632): *******GOT METHOD _dir_open ok!!
06-27 00:22:28.448: I/godot(632): *******GOT METHOD _dir_next ok!!
06-27 00:22:28.448: I/godot(632): *******GOT METHOD _dir_close ok!!
06-27 00:22:28.448: I/godot(632): *******GOT METHOD _dir_is_dir ok!!
06-27 00:22:28.448: I/godot(632): starting to attempt get methods
06-27 00:22:28.448: I/godot(632): *******GOT METHOD _init_audio ok!!
06-27 00:22:28.448: I/godot(632): *******GOT METHOD _write_buffer ok!!
06-27 00:22:28.448: I/godot(632): *******GOT METHOD _quit ok!!
06-27 00:22:28.448: I/godot(632): *******GOT METHOD _pause ok!!
06-27 00:22:28.448: I/godot(632): test construction 5
06-27 00:22:28.448: I/godot(632): running from dir /
06-27 00:22:28.466: I/godot(632): **SETUP
06-27 00:22:28.466: I/godot(632): CMDLINE LEN 2 - APK EXPANSION 0
06-27 00:22:28.507: I/godot(632): *****SETUP OK
06-27 00:22:28.507: I/godot(632): ANDROID MODULES: Nothing to load, aborting
06-27 00:22:28.517: I/godot(632): WARNING: not found: display/driver/keep_screen_on
06-27 00:22:28.543: D/GODOT(632): setVirtualKeyboardHeight: 0
06-27 00:22:28.548: I/Adreno(632): QUALCOMM build                   : 53b4b64, I83a540a04a
06-27 00:22:28.548: I/Adreno(632): Build Date                       : 09/18/17
06-27 00:22:28.548: I/Adreno(632): OpenGL ES Shader Compiler Version: XE031.09.00.04
06-27 00:22:28.548: I/Adreno(632): Local Branch                     : 
06-27 00:22:28.548: I/Adreno(632): Remote Branch                    : quic/gfx-adreno.lnx.1.0.r5-rel
06-27 00:22:28.548: I/Adreno(632): Remote Branch                    : NONE
06-27 00:22:28.548: I/Adreno(632): Reconstruct Branch               : NOTHING
06-27 00:22:28.669: I/OpenGLRenderer(632): Initialized EGL, version 1.4
06-27 00:22:28.669: D/OpenGLRenderer(632): Swap behavior 1
06-27 00:22:28.672: W/GodotView(632): creating OpenGL ES 3.0 context :
06-27 00:22:28.684: I/godot(632): ^_^_^_^_^ newcontext 0
06-27 00:22:28.684: I/godot(632): ^_^_^_^_^ resize 0, 1440, 720
06-27 00:22:28.685: I/godot(632): **FIRST_STEP
06-27 00:22:28.697: I/godot(632): OpenGL ES 3.0 Renderer: Adreno (TM) 506
06-27 00:22:28.749: I/godot(632): OpenSL Init OK!
06-27 00:22:28.754: I/libOpenSLES(632): Emulating old channel mask behavior (ignoring positional mask 0x3, using default mask 0x3 based on channel count of 2)
06-27 00:22:28.766: W/AudioTrack(632): AUDIO_OUTPUT_FLAG_FAST denied by client; transfer 1, track 44100 Hz, output 48000 Hz
06-27 00:22:28.769: D/AudioTrack(632): Client defaulted notificationFrames to 590 for frameCount 1772
06-27 00:22:29.072: I/Choreographer(632): Skipped 32 frames!  The application may be doing too much work on its main thread.
06-27 00:22:29.273: I/godot(632): Main panel is ready
06-27 00:22:30.679: D/GODOT(632): setVirtualKeyboardHeight: 0
06-27 00:22:42.508: V/BoostFramework(632): BoostFramework() : mPerf = com.qualcomm.qti.Performance@619cbc6
06-27 00:22:42.519: I/godot(632): Main panel have input
06-27 00:22:42.519: I/godot(632): Main panel have mouse pressed
06-27 00:22:42.519: I/godot(632): Main panel have left mouse button pressed
06-27 00:22:42.541: I/godot(632): We are changed the scene
06-27 00:22:46.179: E/godot(632): **ERROR**: Unhandled exception: Error: unhandled exception:  [NilAccessError]
06-27 00:22:46.179: E/godot(632):    At: /Users/vasya/.nimble/pkgs/godot-0.7.14/nim/godotnim.nim:838:() - Unhandled exception: Error: unhandled exception:  [NilAccessError]
06-27 00:22:46.179: E/godot(632): **ERROR**: Unhandled exception: Error: unhandled exception:  [NilAccessError]
06-27 00:22:46.179: E/godot(632):    At: /Users/vasya/.nimble/pkgs/godot-0.7.14/nim/godotnim.nim:838:() - Unhandled exception: Error: unhandled exception:  [NilAccessError]

```
The last two lines repeated more than 100 times and then application closes.
I tried to change compilation flags. I disabled threads and tlsEmulation but it have absolutely no effect.

Also I changed android compilation from clang to gcc because of errors (https://forum.nim-lang.org/t/3981) I don't know if it affect to this issue.

Macosx: 10.13.4
Godot: 3.0.4
Android: 7.1.2
Android NDK: r14b