refactored some code
changed some images and perform some cleanup in code to avoid crash
adjusted images
changed image view for post notice in main feed and user feed
populate map with post pin
tweaked UI for posting so that the keyboard is not obstructed when typing in non-English languages
some misc cleanup
show callout when a post is selected
implemented notification views
fixed bugs about unable to load posts from commented view
simplified some code to update user profile
merged master2 branch (working on RCFeed) with master