Fixed Bug: loopDuration could be wrong

The loopDuration could be higher than the sum of all durations when the
float had more than 3 decimal places.
Use int for animationInterval instead of long

With an integer a loopDuration of 24 days is possible which is more
than enough. Long is unnecessary big.
 Fixes missing keycodes, cleans up & sorts existing ones.

 An essential/prerequisite commit for further Input improvements, e.g. #2524
Merge branch 'master' of https://github.com/libgdx/libgdx

Conflicts:
	gdx/src/com/badlogic/gdx/Input.java
Fixed button visual press time.

Jamming a long into a float is not good.
Fixed scene2d.ui widgets for noncontinuous rendering. Other clean up.

closes #2583
closes #2582
#2229
requestRendering when adding an action.
Support Button visual pressed with noncontinuous rendering.
LwjglCanvas and JGLFW support for noncontinuous rendering.
Fixed pasteboard compilation error.
closes #2557, texture unpacker didn't handle indices correctly
Merge pull request #2575 from vaxquis/master

fixes missing keycodes, cleans up & sorts existing ones - an essential/p...
reverted keycode PR
closes #2521, life cycle listener invocation order was not consistent
fixed up Input.java, no idea what's going on there
closes #2509, inconsistent trailing slashes in IOSFiles
closes #2465, freetypefontgeneratorloader was using same name as the font loader itself for an asset, prompting manager.clear to go into an infinite loop
fixed compilation error on debug starter
fixed MusicTest, used String#format, fixed up reflectioncachesourcecreator to allow reflection java.util.* classes.
made gdx-tests-gwt superdev mode compatible, which is now supported by the GWT Eclipse plugin. Yay.