[Documentation] Mention default colours for scalebar

[warnock@…]

as I was working today, I had a scalebar with white (255 255 255) for the COLOR
and nothing for the IMAGECOLOR and was scratching my head as to why the bars
that were supposed to be white were transparent.  the reason is of course that
TRANSPARENT defaults to on, and IMAGECOLOR defaults to white.... so if white was
transparent then of course anything that was white would be transparent.

maybe someone could confirm that?

The documantation make no mention of default colors, and likely should.

[dmorissette]

Was assigned to Raju who is currently away. Reassigned to Kari.

[sdlime]

I'll research and then reassign back to you so you can fix it or reassign 
yourself...

Steve

[jmckenna@…]

let me know if the docs need updating for this.

[jmckenna@…]

working on this now

[jmckenna@…]

after discussions with fred, we discovered that the problem was the description
for the scalebar's TRANSPARENT parameter.  Updated 4.4 and 4.6 mapfile-reference
doc to say the following for transparent:

'Should the IMAGECOLOR for the scalebar be transparent. Note that if any other
scalebar parameters (COLOR, BACKGROUNDCOLOR, OUTLINECOLOR) have the same RGB
values as the IMAGECOLOR they will also become transparent.'