Make raw & parsed commands subclasses of CommandObject rather than having the...

Make raw & parsed commands subclasses of CommandObject rather than having the raw version implement an 
Execute which was never going to get run and another ExecuteRawCommandString.  Took the knowledge of how
to prepare raw & parsed commands out of CommandInterpreter and put it in CommandObject where it belongs.

Also took all the cases where there were the subcommands of Multiword commands declared in the .h file for
the overall command and moved them into the .cpp file.

Made the CommandObject flags work for raw as well as parsed commands.

Made "expr" use the flags so that it requires you to be paused to run "expr".

llvm-svn: 158235