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.
Remove posted runnables as they are run.

If `executeRunnables()` is called from a posted runnable, this commit prevents the runnable from being executed twice.
Merge remote-tracking branch 'origin/master'
Missing exception text.
Fixed TexturePacker.Settings copy constructor.
Y u alwayz commit warnings?!
 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