[#ANDROID-132] Fix optional survey validation, and send button validation.
Update changelog.
Merge branch 'message_center_1_0' into ent_surveys
Merge branch 'ent_surveys' into dialog_surveys_2

Conflicts:
	CHANGELOG.md
Remove old drawables to cut down on SDK size.
1) Apply translucent background to previous Activity when launching ViewActivity.
2) Restyle branding view with new flat design.
3) Check in new Black logo for white background display.
4) Move branding view into foot of survey, apply white background.
Fix mulichoice survey questions. Pre API 8 doesn't seem to handle layout_margin on FrameLayout well. Wrap with another padded FrameLayout instead.
Fix singleline survey questions so the edittext isn't so close to the bottom of the question. Add a tiny bit of space to the other question types as well.