Adds SVG versions of ImageMap custom
icons and conditionally uses them if
have_vector_icons is enabled. If not, we
fall back to the original PNG icons.
Since ImageMap mixes custom and
stock icons, this keeps the icon size
consistent across the UI.
Per Denis Rangelov, tooltips for the
coordinates and area displays as well
as the shortcut menu were added.
Also, removes a reference to IMAP_ARROW
which no longer applies since that icon
was removed in favor of using the stock
cursor icon.
Additionally, the ImageMap-specific icons weren't showing up due to the
filenames not matching the references strings ("imap-polygon" but
the filename was "imagemap-polygon.png"). This patch fixes that by
renaming the strings to match file name.
Partial code style fixes were made as well; a lot more are needed.