Don't map glyphs to unicode non breaking space.
Map missing glyphs in encoding to notdef glyph.
fixes caching of inline images during parsing.

As described in #5444, the evaluator will perform identity checking of
paintImageMaskXObjects to decide if it can use
paintImageMaskXObjectRepeat instead of paintImageMaskXObjectGroup.

This can only ever work if the entry is a cache hit. However the
previous caching implementation was doing a lazy caching, which would
only consider a image cache worthy if it is repeated.
Only then the repeated instance would be cached.
As a result of this the sequence of identical images A1 A2 A3 A4 would
be seen as A1 A2 A2 A2 by the evaluator, which prevents using the
"repeat" optimization. Also only the last encountered image is cached,
so A1 B1 A2 B2, would stay A1 B1 A2 B2.

The new implementation drops the "lazy" init of the cache. The threshold
for enabling an image to be cached is rather small, so the potential waste
in storage and adler32 calculation is rather low. It also caches any
eligible image by its adler32.

The two example from above would now be A1 A1 A1 A1 and A1 B1 A1 B1
which not only saves temporary storage, but also prevents computing
identical masks over and over again (which is the main performance impact
of #2618)
Fix code style in extensions/firefox/content/PdfJs.jsm
Fix code style in extensions/firefox/content/PdfjsChromeUtils.jsm
Fix code style in extensions/firefox/content/PdfjsContentUtils.jsm
Fix code style in extensions/firefox/content/PdfJs-stub.jsm
Fix code style in extensions/firefox/content/PdfJsTelemetry.jsm
Fix code style in extensions/firefox/content/PdfJsTelemetry-addon.jsm
Fix code style in extensions/firefox/content/PdfStreamConverter.jsm
Update |node make lint| to also cover the Firefox specific *.jsm files
Added page break hints in viewer css.
Refactor searching for the SOI marker of inline JPEG image streams
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.
Improve fingerprinting of documents

Fixes two issues:
- #4456 : The first 100 bytes are often not unique as they can be
filled with standard PDF headers - so we use the first 200 KB instead.
(This may be overkill)
- Some documents we encountered have invalid xref ids, which were
always coming out as ‘0000000000000000’ - so we detect that and use the
MD5 instead.
Merge pull request #5508 from Snuffleupagus/jpeg-stream-find-soi

Refactor searching for the SOI marker of inline JPEG image streams
Merge pull request #5445 from CodingFabian/fixImageCachingInParser

Fixes caching of inline images during parsing.
Fix searching for end of inline (EI) images with ASCII85Decode filters (bug 1077808)

This patch changes searching for the end of inline image streams to rely on the EOD marker for the filters: ASCII85Decode and ASCIIHexDecode.
Merge pull request #5124 from jordan-thoms/improve-fingerprinting

Improve fingerprinting of documents
Merge pull request #5406 from Snuffleupagus/lint-firefox-jsm

[Firefox] Enable linting of *.jsm files and update the code style in extensions/firefox/content