Don't map glyphs to unicode non breaking space.
Map missing glyphs in encoding to notdef glyph.
Added page break hints in viewer css.
Add basic support for non-embedded Wingdings fonts

This is a tentative patch that adds *very* basic support for non-embedded Wingdings fonts (a Windows version of Dingbats), by falling back to the ZapfDingbats encoding. Obviously this approach will not work perfectly, but in my opinion it seems to work reasonably well in pratice.

Instead of this very simple patch, another option would be to try and include more complete glyph data for Wingdings, e.g. a Unicode map and glyph widths, similar to what was done for ZapfDingbats.
However there is, in my opinion, one important difference between Wingdings and ZapfDingbats: ZapfDingbats is part of the 14 standard fonts, which in previous versions of the PDF specification was assumed to be available in PDF readers. To improve compatibility with older files, it thus makes sense for us to include data for ZapfDingbats.
However Wingdings has never been a standard font in PDF files, hence PDF files using it *should* thus contain all the necessary font data.

Given the above, I thus believe that it should be OK to fall back to ZapfDingbats for now. If non-embedded Wingdings fonts turns out to be *a lot* more common, then we can revisit this later.

Fixes 4301 completely.
Fixes 4837 almost completely. With this patch the bullets are displayed correctly, but the arrows are not of the correct type.
Fixes `artofwar.pdf`, pages 14 and 15.
Merge pull request #5510 from dustyrockpyle/master

Added page break hints in viewer css.
Merge pull request #5463 from Snuffleupagus/wingdings

Add basic support for non-embedded Wingdings fonts
Merge pull request #5379 from brendandahl/nbsp

Don't map glyphs to unicode non breaking space.
Test case for issue 5481
minor improvements and code cleanup for canvas.js
Merge pull request #5562 from timvandermeij/progression-tests

Test case for issue 5481
Merge pull request #5446 from CodingFabian/minorImprovementsInCanvasjs

minor improvements and code cleanup for canvas.js