Add ToUnicodeMap class.
Add IdentityToUnicodeMap class.

When loading the PDF from issue #4935, this change reduces peak RSS from
~2400 to ~300 MiB, and improves overall speed by ~81%, from 6336 ms to
1222 ms.
Simplify isIdentityUnicode detection.
AES cipher: make padding optional

Fixes #5152
Preserve reference fragment in Chromium URL router

Because removed reference fragments are no longer automatically copied
thanks to https://code.google.com/p/chromium/issues/detail?id=354653
Merge pull request #5153 from Rob--W/crx-preserve-reference-fragment

Preserve reference fragment in Chromium URL router
Merge pull request #5154 from Rob--W/aes-padding-5152

AES cipher: make padding optional
Adds image and mask features, fixes clippath
Reduces amount of used memory during PNG creation.
Merge pull request #5162 from yurydelendik/pramodhkp-fixupgstate2

[SVG] Reduces amount of used memory during PNG creation.
only convert in IE9 if the requested responseType is actually an arraybuffer, otherwise just return the responseText. That way the compatibility.js does not break other frameworks like angular that not always want an array from xhr requests.
Nit fixes for svg.js
Merge pull request #5164 from timvandermeij/svg-nits

Nit fixes for svg.js
Remove old unused code from PDFView.close()
Merge pull request #5150 from nnethercote/toUnicode

Fix #4935
Merge pull request #5160 from tomdw/feature/fix-angular-compatibility-ie9-conflict

only convert in IE9 if the requested responseType is actually an arraybu...
Removes bytesToString/stringToArray conversions in the font.js
Removes stringToArray
Fixes searchRange calculation
Merge pull request #5163 from yurydelendik/fontrefact

Refactoring of OpenType/TrueType font construction