GlyphMapWidget now reports context menu requests when secondary
clicking the map. This also adds a new Select All action and updates
the Copy Character action to work on multi-glyph selections. Glyph
navigation actions have been moved to a separate Go menu, as is
common in other apps.
Fixes an edge case in which mousing down on the active glyph within
a larger selection would reset the selection but fail to update the
glyph map. Now we can grow or shrink the selection by dragging the
active glyph even after an initial selection is made.
This patch makes background a bit darkened so that it is possible to
distinguish out of range area from glyphs that are just not drawn.
The default background color is also changed to Window so that it looks
good in more themes.
Previously, if it was displaying N glyphs per line, then you changed
font to one that was a drastically different size, it would continue to
display N glyphs per line until you resized the window. Now, we
immediately recalculate how many to show, so that they fill the
available width. :^)
