[cmap] Fix format 13 parsing and serializing

Language is 32bit in format-13 subtable, not 16bit.
[cmap] Allow fonts that only have a format-12 or format-13 subtable
Make Process() a method of ots::OTSContext

Makes it easier to access the context’s private members without the ugly
getters.
Fix crash

It makes no sense to access “it->first” if “it == table_map.end()”, a
thinko introduced in 9f5b6e2e6a5c0182e4c89233aff8a4f6414d55e0.
Simplify
#undef the TABLE_NAME and DROP_THIS_TABLE macros at the end of each file that uses them
[doc] Update Windows build instructions

Make it clear that both zlib source and binary library are needed.
[ot-sanitise] update documentation

The docs are no longer correct since ac7aa8e.
[doc] import documentation from the old project

Closes #22.
[doc] misc improvements
[layout] accept 0 lookup, feature or script offset

Having null offsets for those is perfectly valid, so accept that and
skip parsing the relevant list in this case.

This commit is best viewed with --ignore-space-change.

Fixes #4.
Implementation of the woff2 format changes proposed by the W3C working group.

  * size of compressed font data is in the woff2 header
  * bits 5 and 6 of the table flag byte are reserved, must be 0
  * bit 7 of the table flag byte is the transform bit

This ports the decoder part of the font-compression-reference change:
https://code.google.com/p/font-compression-reference/source/detail?r=22e2c328288610e63c03e8de0b9c18b1b926cff6

R=tkent@chromium.org

Review URL: https://codereview.chromium.org/216043003
Remove unused kShortFlagsContinue.

This will fix Chromium's clang build error.

R=tkent@chromium.org

Review URL: https://codereview.chromium.org/216263002
Fix brotli include for all OSs

Related to googlefonts/fontbakery#305.
[OTS] update woff2 implementation

Manually ported from font-compression-reference repository.

https://code.google.com/p/font-compression-reference/source/detail?r=47c5016d7f20363602601aa2624229482b5c2e50

TEST=compiled
R=ksakamoto@chromium.org

Review URL: https://codereview.chromium.org/261563002
fix error messages in layout.cc that print a 4-char tag
Make compiler happy when OTS_DEBUG is defined
Fix CFF parsing with charset format 0 and FDArray format 0

The code for those two was using the variable glyphs, but glyphs
was only initialized when CharStrings was read, which is typically
after the other ones.  Use num_glyphs from maxp instead, and add
checks to make sure it matches the one from CharStrings.