Fixed imports in headers in Support/AFNetworking
[Readme] Fixed a syntax error in example code

Seems as if I had been too swift
MRProgressOverlayView + UIScrollView.contentInset

Properly centering `MRProgressOverlayView` when it's added to an `UIScrollView` that has `contentInset` set.
Merge pull request #54 from marcelofabri/patch-1

MRProgressOverlayView + UIScrollView.contentInset
Fixed a bug in Example app
Merge branch 'master' into fix/53_compiler_warnings
Fixed warning from missing cast