Get trailing-wspace deletion to look at more files

Now it also looks in .bib and .doc files

Trailing-whitespace deletion script now handles tabs also

There is also a -n option to see what it might affect without actually
going through with the replacement.

Slightly fiddle with delete-trailing-ws script invocation.

Aim is to make it easier to find out what it does after an absence.

delete trailing whitespace (in lem files too)

Modify delete-trailing-ws tool to do its thing in .tex files too.

New tool to find and fix files containing trailing white-space.