Post retrieval added

Added Feed view
Added Post View
Added Post Class

Timeline feed can now be viewed suuceesfully.
Posts can be selected from feed view and viewed in detail.
Images and videos in posts can be loaded successfully by tapping on
them in the detail view.
Event title is now displayed in navigation bar.
Photo title is now displayed in navigation bar.
About section now shows description text instead of about text.
Minor code cleaning.

Added FBsession handler in AppDelegate [Resolved non authentication
issue].
Added feed icon for menu
Added app icon

Removed old menu icons