Added node conditionals and optimizations for FlxUI9SliceSprite
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel-ui into dev

Conflicts:
	flixel/addons/ui/FlxUI.hx
	flixel/addons/ui/FlxUI9SliceSprite.hx
	flixel/addons/ui/FlxUIDropdownMenu.hx
	flixel/addons/ui/FlxUISubState.hx
	flixel/addons/ui/FlxUITabMenu.hx
	flixel/addons/ui/FlxUITypedButton.hx
Merging stuff
Compatibility (HaxeFlixel/flixel@8595c4fe71451efe23009fd29855f932e2cff1a6) + fix for FlxUIDropDownMenu (was still using strings for 9-slicing)
Compatibility update for HaxeFlixel/flixel#805
Keyword order change:

static public function
->public static function
Keyword order change:

static public var
-> public static var
Keyword order change:

inline public static var
-> public static inline var
Merge pull request #35 from HaxeFlixel/keyword_order

Keyword order
Remove html tags from comments

(includes <code>, </code>, <br> and <br />)
Update haxelib.json
Add CHANGELOG.md
Event flow re-factor
More re-factoring: changed sender from Dynamic to IFlxUIWidget in event functions where possible
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel-ui into dev

Conflicts:
	flixel/addons/ui/FlxUIAssets.hx
Changing event signature so data and params are separate. "data" is always a primitive or object, "params" is always an array.
Refactoring so no uiEventCallback variables are needed, events now handled statically
Downgrading error to warn.
D'oh. Fixed stupid typo.
FlxUI compile fixes