Fixed 'remove file' command not removing editor
Fixed previous oversight of current editor not corresponding to currently selected project browser item.
Setup UITrees and UITreeContainers to differentiate between node selection by keyboard and by mouse. Removed ability to optionally select a node in UITreeContainer::scrollToNode() method. Removed ability to travel to first child node via right arrow key (use down).
Arrow-key nav no longer opens files in PolycodeProjectBrowser as a side-effect -- use the enter key, right arrow key, or single-click mouse.
Hooked up IDE property controls to the Undo/Redo system and implemented Undo/Redo in the screen editor for most actions. ColorPicker and HSlide no longer send out change events on drag, only on release, multiple fixes in the IDE
Fixed 2d editor copying and pasting stuff when not in focus
Fixed NumberProps and StringProps not returning values correctly. Fixed sprites crashing when framewidth is larger than the sprite size.
Added resizing support for IDE editor props. Added resize support for UIComboBox. Added resize support for UIHSlider, fixed resizing for UITextInput. Added padding to UITextInput's scissor box so descenders don't get cut off. Made textfields slightly darker.
Fixed SliderProp value overlapping with the slider
Merge pull request #283 from TheCosmotect/master

Fixed IDE 'remove file' command not removing editor
Fixed crash resulting from closing the last editor in the IDE not setting current editor to NULL
Merge pull request #303 from TheCosmotect/projbrowser-selection

Arrow-key nav/selection no longer opens files as a side-effect in PolycodeProjectBrowser
Polycode will now ask you if you want to save unsaved files on quitting. Mac only for now
Fixed UITextInput hanging in some cases