Sound Editor Proposal

[RobertBColton]

This is just a draft of what I think the sound editor should maybe look like. I feel it's a little more organized and compact than LGM's. Most notably, the sound effect options (chorus/flanger/reverb) are missing because ENIGMA hasn't implemented them yet, and they are technically deprecated in GMS because they complicate the sound embedding unnecessarily for a feature that few people need.

The only issue with this pull request perhaps is the default layout margin/spacing issue discussed in #18

[RobertBColton]

Alright, let's get this in. I'm making a couple of last minute changes here.

• I now resize the new QMdiSubWindow to the size of the editor widget to fix the issue with them all opening too small
  https://bugreports.qt.io/browse/QTBUG-70305
• I've disabled the plugin call to test printing of all the JDI discovered resources since it's making the startup really long
• I've removed an unused include to QMdiSubWindow in BaseEditor
• I'm going to merge without the format or compression options present on the sound editor since we won't be adding the functionality for a while
• Changed the AppVeyor configuration to not increment the build number for pull requests since those aren't official builds

I've filed other Qt bug reports on new issues too:
https://bugreports.qt.io/browse/QTBUG-70306
https://bugreports.qt.io/browse/QTBUG-70307