add Gamepads API and java implementation
add Gamepads html implementation
load and init jinput correctly for gamepad api
fix html gamepads implementation
fix logging in JavaGamepads
add missing license headers
fix java compile
Merge branch 'master' into gamepads

Conflicts:
	core/src/playn/core/Gamepad.java
	core/src/playn/core/Gamepads.java
	core/src/playn/core/GamepadsStub.java
	html/src/playn/html/HtmlGamepad.java
	html/src/playn/html/HtmlGamepadJavascriptObject.java
	html/src/playn/html/HtmlGamepads.java
	java/src/playn/java/JavaGamepad.java
	java/src/playn/java/JavaGamepads.java
	java/src/playn/java/JavaPlatform.java
	tests/core/src/main/java/playn/tests/core/GamepadTest.java