Extended OakTextView API

Added `scopeAsString` method to retrieve current scope as NSString
Use NSHost to obtain computer’s name
Use NSNumberFormatter class method

Once we drop 10.7 support we can avoid NSNumberFormatter entirely by using ‘localizedStringWithFormat:’ with ‘%lu’.
Use localizedStandardCompare:

This is instead of our custom displayNameCompare: which has now been removed.
Use new focus ring API (10.7)