Activity Display changes

- added isGeneral field in Feature
- added header views in DetailsActivity and HomeActivity
- actionbar icon is now clickable as "send home" action in every EnvivedFeatureActivity
Merge branch 'envived-aiwo' of https://github.com/asorici/envsmth into envived-aiwo

Conflicts:
	EnvSocialApp/src/com/envsocial/android/DetailsActivity.java
Presentations by session

- added the fragment for viewing the schedule of presentations on a by session view
- added the SocialMediaFeature model in coresql/models.py
Merge branch 'envived-aiwo' of https://github.com/asorici/envsmth into envived-aiwo
Allowing AnnotationResource to always return data, when creating a new annotation instead of just the status code