tkdiff Code

* Make opening file dialog know where it started from, and start in the
same directory as the first file when looking for the second one. Will
still have to do something about when it's started with a double click.
* Detect PVCS by environment variable (patch 1839361 by nafmo)
* Update BitKeeper support (patch 3053551 by wscott)
* Mercurial support (patch 1867700 by damonmc)
* Rudimentary Git support (patch 1836293 by cecilh3)
* add help menu items to report versions of wish and diff

This commit was manufactured by cvs2svn to create tag 'REL-4-1-4'.

Finalize Windows stuff

Instructions to build stand-alones, and InstallJammer config file

Script to make a Starpack for Windows

Remove no-longer-needed Mac font work-around

Ignore -u option from svn for usage "svn diff --diff-cmd=tkdiff"
Perforce support for P4CONFIG environment variable
Remove an old font work-around for Mac, but add a new one for tk8.5 on Windows
Fix duplicate keyboard accelerator for Preferences

Added Payton Quackenbush's patch, to ignore -u, as occurs when called from subversion.

This commit was manufactured by cvs2svn to create tag 'REL-4-1-3'.

A README for MacOS, to explain how to install it, and how to create an alias for command-line use.