Add basic support for ZapfDingbats

This patch adds support for the `ZapfDingbats` encoding, and should thus fix issues/bugs with titles like: "check&nbsp;marks rendered as a number (4)".

Compared to the rendering in Adobe Reader, many of the glyphs doesn't look as nice. However, it should still be a *marked* improvement compared to the current situation where we don't even attempt to draw the correct glyphs.

/cc @yurydelendik 

Fixes #1577.
Fixes #2738.
Fixes #3032.
Fixes [bug 846359](https://bugzilla.mozilla.org/show_bug.cgi?id=846359).
Fixes [bug 846675](https://bugzilla.mozilla.org/show_bug.cgi?id=846675).

**Edit:** I added support for additional (depreciated) Mac OS specific dingbats glyphs, to make sure that we handle older documents correct. Note that we already, as for the "standard" dingbats glyphs, include width data for these.
Also, I found a document that can be used for testing: http://www.w3.org/Style/XSL/TestSuite/contrib/XEP/Tests/zapf-dingbats.pdf (from http://www.w3.org/Style/XSL/TestSuite/contrib/XEP/).
Should we include this as a "linked" test?