* Add new rewrite_color method to GD objects that will rewrite one
color to another. Clean up manpage.
* Add a "delete" method to the created GD objects. The result is the
same as doing a rename $object ""
* Add argument count validation to the width and height methods.
* Use interpreter-associated data for the next object number for
GD objects created with a name of "#auto" rather than a global.
Although this should not have caused any problems with multiple
threads using tclgd simultaneously, better safe than sorry.
* New function, tclgd_imageRewriteColor, rewrites one color to another
for indexed and truecolor images. Not used yet.
* Fix possible memory leak in tclgd_channelNameToIOCtx
* Fix memory deallocations to use ckfree() instead of gdFree() (Issue 1)
* Correct "rectangle" method to create a non-filled rectangle. (We were
incorrectly calling gdImageFilledRectangle instead of gdImageRectangle.)
* Expand docs.
