Merge pull request #1 from jessedc/bug/Wsign-conversion-compare

Fixes for -Wsign-conversion, -Wsign-compare
Restructured project into a workspace with separate projects for EZForm library and demo app.
Ramps compiler warnings up to 11.
Adds Retina4 default image.
Converted to ARC.
Converted to modern Objective-C syntax.
More Obj-C modernisation: auto-synthesis and enum types.
Updates source copyright messages.
Updated README and LICENSE.
Updates "-ObjC" requirements.
Updated README.
Fixes a small error in README sample code.
Adds autoScrollForKeyboardInputVisibleRect property and improves automatically adusting scroll view insets for keyboard visibility.
Updated for stricter compiler warnings in latest llvm.
Adds -Wno-unknown-warning-option to allow new clang warnings to be used without breaking backward compatbility.
Adds a gitignore.
Fixes inset adjustment when auto adjusting scroll view for visible keyboard.
Adds a scroll view based form demo.
Minor fix to registration form field demo.
Fixes scroll view insets updating when keyboard size changes.