Starting work towards
https://sourceforge.net/p/tuxpaint/feature-requests/213/
The ability to 'apply' a label to the canvas, making it permanent
(as if added using the "Text" tool instead).
Removed unused "label rotate" option's code (and hence addressed
a bug we didn't relalize when choosing the "Label" tool while in
in "--nostampcontrols" mode; the unused "rotate" button would appear).
Replace the somewhat-recently-added "nothing" item in the tool bar
with the "Fill" tool, which has been converted back from a Magic tool
to a regular tool.
Also, change bash "==" to sh "=" in "if [ ... ]" tests in Makefile.
Also, link to math library (via "-lm") to make sure "max()" is available to
magic tools.
Also, add missing mention of "--newcolorslast" and "--newcolorsfirst" to manpage.
