Fix merge of 'moly/fix_issue_185'

See 8b1424e7c3d4e24c357b0cac5b4c659c0b7cbf54

I dun goofed when manually fixing the merge of
https://github.com/FlixelCommunity/flixel/pull/102
Move Flixel source to 'src' folder

Finally!
Increment version number to v2.56

That makes it official! :D