[trace] fixing Issue 583 partially - now recording a string works in a trace directive

git-svn-id: http://umple.googlecode.com/svn/trunk@4161 6ebf9d09-8eb1-0036-9d08-68c07d1b990a
Attributes mapping to Alloy finalized
- String, Date, Time (Umple) -> String (Alloy)
- ObjectName (Umple) -> ObjectName (Alloy)
- Added real estate example from UmpleOnline as a test case

git-svn-id: http://umple.googlecode.com/svn/trunk@4162 6ebf9d09-8eb1-0036-9d08-68c07d1b990a