Add experiment listener interface.

Also rename addRun to addExperimentRunGroup.
Fix TODO.
Some more logic fixes.
Rename run button id.
Add an IExperimentRunListener interface.

Move the camera experiment view completely out of of the main experiment
class.
Separate view from the accelerometer experiment run.
Use a view pager for the recording.

Not finished yet.
Remove unnecessary try catch.
In case the preview is running: stop it first.
Add functionality to activate an experiment run group.

Items in a group are init or destroyed if needed.
Finally make the view pager working.

The android view pager is just broken. Reset the whole adapter instead
of trying to reuse existing items.