Bug 19937

Even though the tcsh man page stats that "tcsh is an enhanced but
completely compatable version of the Berkley UNIX C Shell, csh(1),"
there are a few important differences.

In a previous pr, I stated that prompt now treats control charcters
differently.  Upon analisys of the tcsh man page, I didn't find
the root cause:  the "command-line editor"  This feature is turned
on by setting envitonment variable edit.  Unsetting this variable
causes prompts with control charcters to work correctly. (FWIW, I
don't consider unsetting the edit variable to be THE fix for this
issue.  It needs to be addressed via other means)

Historically, setting the shell variable filec turns on file name
completion.  In tcsh this is not the case, it's turned on by the
edit variable.  Unsetting edit, with filec set disables filename
completion.  Of course, setting the edit variable again causes
filename completion to work in the manner one would expect (well..
in the manner that tcsh does filename completion -- it's not
exactilly like csh, but it's close enough for goverment work).

There is, however one issue in file name completion that also should
to be addressed.  In csh, the completion charcter is (be default)
the escape key (^[).  Of course it's <TAB> in tcsh.  Tcsh does seem
to support the use of the escape key as the completion charcter,
but there is one large difference:  the user must press escape
twice before the shell attempts to complete the command.

There are of course, many more incompatabilities, most of which
are rather minor but annoying in any case, but they all seem to
relate to the command-line editor in one mannor or another.  The
two above are the two I spotted litterily in less than 1 minute of
use.

How-To-Repeat: set edit, then unset edit and note the differences.