Crash when using "Terminate running process" on linux
On linux, if you run a program from Aporia and then choose "Terminate running process" from the menu then Aporia crashes.  For example, use this example program in Aporia:

```
# a simple html server
import
  jester, asyncdispatch, htmlgen

routes:
  get "/":
    resp h1("Hello world")

runForever()
```
...and run it from Aporia with the **Tools -> Compile & run current file** menu option.  Then, when the program is running, use the **Tools -> Terminate running process** menu option.  The example program will quit, but Aporia will also quit unexpectedly.

I have a hack which allows me to keep using Aporia, which may shed some light on the problem.  You can see my hack here: 6b008db5cf38132b4e9eb91bba91bbf591006928 where I'm checking to see if the process is still running before calling `p.waitForExit()`.