Changes by: Jason Hickey (jyh at cs.caltech.edu)
Date: 2006-04-12 10:18:29 -0700 (Wed, 12 Apr 2006)
Revision: 9066
Log message:

      Handle alias expansion more carefully.  If the command includes any quoted
      text, it is not alias expanded.
      
         Shell. +=
             foo(argv) =
                 println(Foo)
      
         osh>foo
         Foo
         osh>\foo
         foo: command not found
         osh>X = o
         osh>fo$X
         Foo
         osh>Y = $'o'
         osh>fo$Y
         foo: command not found