JUSTIFY or ALIGN keyword for scalebarObj...

[Steve Lime]

Hi all: I've been putzing around with scalebars a bit and noticed that the current code centers the bar in the image. Works fine in
many cases, but I've found it desirable to be able to specify the justification within the image so the scalebar itself is aligned left,
right or center. So, I'd like to propose adding a keyword, either JUSTIFY or ALIGN to the scalebar object. I figure it could be used
with labeling down the road too. 

Any objections? Preferences on the keyword name?

The change in mapscale.c is trivial so I don't think this needs a RFC.

Steve