This parameter controls texvc background color. Can be set to output transparent background
* Added $wgTexvcBackgroundColor parameter to DefaultSettings with value 'rgb 1.0 1.0 1.0'
* Changed Math.php to call texvc with new parameter
* (bug 6721) missing symbols ulcorner, urcorner, llcorner, lrcorner, twoheadrightarrow, twoheadleftarrow
* (bug 7367) Hyphens sometimes erroneously appended to equations when not converted to PNG