Added elastic easing functions.
Merge pull request #791 from steverichey/dev

dont use the same inthelper twice in the same function
SoundTray / FocusLostScreen: Don't take camera zoom into account, fixes HaxeFlixel/flixel-demos#69

Otherwise they don't center correctly on games with camera zoom != 1
Replace UInt by Int
FlxGamepad: Initialize dpad vars to prevent neko crash

Properties always need to be initialized on neko.
Fixed a typo, should be elasticInOut, not elasticInOunt.
Merge pull request #789 from goshki/dev

Added elastic easing functions
Compile fixes

Compatibility with the haxe dev branch (no more skipping imports on non-nullable parameters)
Removed TexturePackerFrame.hx, not needed anymore
Some more compile fixes for flixel-conditionals
FlxG.openURL(): Don't hardcode the target String
FlxG.keyboard: Remove pressed, justPressed and justReleased to get rid of dynamic typing

- the "any"-functions provide the same functionality, just need to pass an array instead
- also makes the API clearer (the "or"-connection between params isn't immediately obvious for a function named "pressed()")
- less error-prone due to proper static typing instead of Dynamic arrays + makeVarArgs(), might also be faster
- removed ability to pass integers to checkKeyStatus(), there's checkStatus() for that already
FlxKey: Use spaces instead of tabs for formatting

Tabs mess things up when using them for anything but indentation / don't look consistently everywhere
Get rid of a few Dynamic types, remove unused MotionType enum
Remove constructor params from the Log / Watch / Console / Stats windows
BitmapFrontEnd: Remove OpenFL 1.0 comptability logic

We shouldn't encourage using outdated OpenFL versions, also, this seems to require extra conditionals for chxdoc to work
Merge FlxG.keyboard into FlxG.keys
FlxSpriteUtil: Return FlxSprite / FlxObject where possible to allow chaining

Also reordered the params of alphaMask() so that the sprite param is first, making it compatible with Haxe's using keyword.
FlxSound.proximity(): Remove reference to FlxCore 

FlxCore was a flixel 1.x class afaik.
Readme: Add bitdeli badge
Style cleanup on FlxGame.