Added implementation for Back button in Android.
Merge pull request #98 from e-ucm/BackButtonImplementation

Added implementation for Back button in Android.
Adding support for setting the initial scene on the scene elements list
Merge branch 'master' of https://github.com/e-ucm/ead into editor-initialscene
Moved schema to engine
Renamed schema artifcat to engine-schema
Adding support for setting the initial scene on the scene elements list
Merge pull request #100 from jtorrente/editor-initialscene

Editor initialscene