rewrote InterpolationTest

- added time marker in the graph
- added ability to change duration using ctrl + scroll
- path is now drawn
- doesn't need any assets
I know this isn't of any importance, but I had to rewrite it anyway, so I added a few things.
Update InterpolationTest.java
replaced generated assets with test assets
fixed stupid NPE

Skin was local
Merge pull request #861 from dermetfan/master

rewrote InterpolationTest
updated some poms
Merge branch 'master' of https://github.com/libgdx/libgdx
[maven-release-plugin] prepare release 0.9.9
[maven-release-plugin] prepare for next development iteration
fixed up imports in bullet test, updated gdx-setup ui config
included x86 in default project generated by gdx-setup-ui
fixed fetch.xml
Default encoding to UTF-8.
Resizability for window.
Merge branch 'origin/master'