Convert -(NSString *)message, -(NSString *)name, -(GTObject *)target, and -(NSString *)targetType to properties.
Update GTTag properties to use modern objective-c syntax.
Add GTTagSpec and delete GTTagTest.
(The previous commit accidentally made those changes, this just updates the Project Settings)
Make new properties readonly.

(Style fixes as well)
Documentation.
Convert targetType from NSString to GTObjectType.
Make -(NSString *)description use dot-syntax.
Reverse polarities.
Documentation++.
Whitespace—.
More whitespace--.
Hopefully fixes spacing issues.
Whitespace— Again.
Merge pull request #253 from PiersonBro/Give-GTTag-Some-Love

Give GTTag Some Love