Update to ARC
Harmonize coding style
Use dictionary literals
Remove unneed WebView extension

We no longer support version of Mac OS X, where `setDrawsBackground:` is not supported.

Also removed mention of 10.5+ in the help menu.
Remove redundant storage keyword for property
Do not use bool in .mm files

Also, change variable to camelCase.
Prefer Foundation data types (e.g., NSUIntger)
Make class method an instance method