Relates to #6

ToolingAPI
* added ToolingAPIAuthorizationException
* submitRestCall(string, string, Object) method now throws
ToolingAPIAuthorizationException if a CalloutException occurs where the
endpoint is not authorized.

UmlService
* reorganized methods so that private methods appear first then public
and all methods are sorted alphabetically.
* added new makeException(ToolingApi.ToolingAPIAuthorizationException)
method to handle endpoint authorization issues.
* other methods updated to make use of new makeException method
* spaced some of the methods out some for readability.