Crash when close filer
### Version

moe v0.3.0

Git hash: 133083597e899df716c6defc4fc28eccf26050b9
Build type: Debug

### Environment

OS: Arch Linux
Terminal: Alacritty

### Category

Major — The software does not fulfill the task it is designed for.

### Steps to Reproduce

1. `moe ./` - Start filer mode
2.  `:sv` - Open more filer
3. `Ctrl-k` - Move to the next filer window
4. `:q` - Try to close the window (`Error: Not an editor command: :q`)
5. `:q` - Try again
6. Crash

### Detailed Description

/home/fox/git/moe/src/moe.nim(102) moe
/home/fox/git/moe/src/moe.nim(98) main
/home/fox/git/moe/src/moepkg/mainloop.nim(402) editorMainLoop
/home/fox/git/moe/src/moepkg/editorstatus.nim(863) update
/home/fox/git/moe/src/moepkg/editorstatus.nim(589) updateStatusLine
/home/fox/.choosenim/toolchains/nim-2.0.0/lib/system/fatal.nim(53) sysFatal
Error: unhandled exception: index 1 not in 0 .. 0 [IndexDefect]