Linux64 build was segfaulting with the following error: "Program received signal SIGFPE, Arithmetic exception. 0x000000000047f352 in hx::Mod (inLHS=0, inRHS=0) at /usr/lib/haxe/lib/hxcpp/3,0,2//include/hx/Operators.h:93"
fixes #651: if you destroy() a FlxObject, set the exists flag to false
Negative offsets, and minimum positions were not calculated correctly
merge upstream/dev
Fixed gamepad to use this.length instead of members.length when calculating alpha.
Clean up some code in FlxSprite.
Merge branch 'dev' of https://github.com/HaxeFlixel/flixel into dev
Fixed set_alpha for FlxGamePad to account for null members.
Optimization: Using hashed floating point numbers as keys to TileSheetFrames. Reduces the number of string allocations performed.
Merge pull request #657 from newtzgames/master

Fixed FlxGamePad alpha calculation.
Merge remote-tracking branch 'origin/master' into dev

Conflicts:
	src/org/flixel/system/input/FlxGamePad.hx
Oopsie... I forgot FlxGamepad was renamed to FlxVirtualPad. I manually integrated the null check fix.
Revert "Negative offsets, and minimum positions were not calculated correctly"

This reverts commit a3e460809a0111af45fd77d0501239677d786973.
This check was added, but not needed
Replacing mp3 & wav files with ogg files, to prepare for openfl 1.1
Fixing some improper inlines.
Fixing crash issue on Neko target.
Made default engine sounds be .wav (sorry for file size increase) - it's the only true cross platform option for now...
Merge pull request #656 from ArtBIT/dev

Linux64 build segfault fix & destroying a FlxObject should set exists to false
Fixing crash that happens on native targets because of weak typing information.