Fix SDL joystick
SDL host sets MOAIEnvironment values for screen size (all OS's) and DPI (Windows only)
support screenDpi to Linux
fix screen DPI for Linux;
Merge pull request #1026 from patrickmeehan/develop

Changes to MOAIActionMgr, MOAIInputMgr, graphics resource lifecycle
Merge pull request #1028 from daltomi/sdl_joystick

Fix SDL joystick; minor ref.
Merge pull request #1031 from DanielSWolf/environment-info

SDL host: set additional MOAIEnvironment values
fixed xcode compile error