Fixes #166 - Back button destroyed by title change

- Saves the post directly instead of content that hasn't changed.
Fixes #193 - Dismiss popover on disappear
Fixes #186 - UI breaking when replying to comment

in Notifications -> Comment

Removed unnecessary BOOL that had the opposite state that was expected for hiding the keyboard. If cancel worked, iPad keyboard button did not, and vice-versa.
Fixes #195 - Retain current popover on rotation

Previously, it was being destroyed and recreated, thus losing the place the user was at in their camera roll.
#154 - Replace all instances of NULL with nil when used in Objective-C files to prevent potential logical comparison issues
#154 - Replaced instances of false & true with NO & YES
#154 - Replaced remaining instances of false with NO
Rename iOSCorrectedTextView to uppercase 'i'

Ref: https://github.com/wordpress-mobile/WordPress-iOS/commit/b7c4ca19eb23bac84bea00601fb301c18ef3610f#diff-5bbec26060fc3c86d4c6ba8f3c44392aR2
Fixes #222 Set exclusive touch on editor toolbar
Fixing build warning from SidebarTopLevelView.xib.
Fixes #181 Use navcontroller toolbar for comments

Uses the navigationController toolbar with the items defined in the xib.
Fixes #227 - Set a default value for the BOOL used in a conditional
Removed unused instance variable in app delegate
Fixes #167 - Add back button for post media item
Fixes #170 Tint colour to white for media item bar

@aerych mentions that "We should use the same bottom toolbar background style used in other places in the app." but the black gradient bar is seen in many places.
Static analysis fixes

- Garbage CGFloat
- BOOL pointer used improperly
Static analysis fixes - BOOL pointers
#196 - Add 'Tap here to begin' for quick photo
Fixes #194 - Dismiss any actionsheet on post media

- Uses currentActionSheet, not just addMediaActionSheet.
Removing UIImagePickerControllerReferenceURL checks.

Don't need to check for this anymore as it's been in the SDK since 4.1