[Ch20 - update] Added results from intent

Added:
+ inter-activity communication where CrimeFragment starts
CrimeCameraActivity for result
+ CrimeCameraFragment now returns filename which is obtained by
CrimeFragment

To-do:
+ Update model
[Ch20 - update] Added Photo class, Crime model updated

Added:
+ Photo class to wrap image filename
+ Updated model to include Photo object
+ Crime JSON Object now includes a Photo JSON Object to be serialized
upon saving
+ Updated View to include thumbnail ImageView (not wired up yet)

To-do:
+ Wire up thumbnail ImageView
+ Write PictureUtils helper function to scale / optimize large images