Android: add a SeekBar to show animation progress

contrib/mobile/Android/res/drawable-hdpi/ic_list.png

contrib/mobile/Android/res/drawable-hdpi/ic_mesh.png

contrib/mobile/Android/res/drawable-hdpi/ic_settings.png

contrib/mobile/Android/res/layout/control_bar.xml

contrib/mobile/Android/src/org/geuz/onelab/Gmsh.java

contrib/mobile/Android/src/org/geuz/onelab/MainActivity.java

...rib/mobile/Android/src/org/geuz/onelab/ModelFragment.java

contrib/mobile/androidGModel.cpp

contrib/mobile/androidGModel.h

contrib/mobile/drawContext.cpp

contrib/mobile/drawContext.h