Simple bug fixes and improvements

[TimBoettcher]

Hi,

I tested the editor and it looks good so far, especially accessibility-wise. (Quest 5 had a few accessibility issues, and since Electron is essentially a Chromium browser running a JavaScript powered website, these issues are, for now, fixed as per default).

I do have a couple bug fixes/accessibility improvements for you, though:

• Add mnemonics to menu items. By placing an & in front of the menu item labels like &File, you ensure Windows users can access the menu using alt + f. VITAL for accessibility, as there is no other way to access the menu otherwise (and even though many menu items have access keys, I couldn't see these access keys before I added the mnemonics).
• The folder created when exporting to JavaScript is titled Game_name.. The trailing period, courtesy of Game_name**.**asl6, leads to issues on Windows. Suggested fix: Ammend file extension constant to ".asl6" and ".aslx" respectively or replace "." + file extension constant instead of just file extension constant.
• Saving the game prints an error in the console, albeit not a "show stopper" -- apparently a function is missing.
• Use Constants.QUEST_JS_DIR instead of just QUEST_JS_DIR in export to JavaScript. Also, in this case, the applications looks for the ququestjs folder one level too high, probably because of the leading ../. However, if I remove that, questjs doesn't get found on startup. I recommend farther investigation.

I'm willing to get on board and help you with the editor (also ensuring accessibility) if you'd like that, but currently that's a bit tricky: The wiki isn't really helpful to new developers, and I couldn't find (a) file(s) that would help me get a feel for the project, so I mostly had to figure things out on my own,is pretty time consuming.