implemented override on setContentInset

- This needs to also set the contentView frame to trigger a new layout.
- I also removed the dispatch_async on the layout notification because this unduly delays the change of the frame until the next runloop which might cause problems
- for the frame to be already updated I moved the super setFrame to before setting the content view. This is needed by the contentViewDidLayout: event.
- To still insure that view changes occur on main thread I added the "old style" if and calling the selector on main thread if it is not.

Generally

fixes #326
Updated podspec for 1.3.2
Fixed required version 1.1 in podspec
Fixed problem where frame would get stuck on zero using contentInset

Now the frame height is preserved
Moved content view ivar to header to allow access from subclasses
Merge branch 'master' of github.com:Cocoanetics/DTCoreText

Conflicts:
	Core/Source/DTAttributedTextView.h