add monospace font Anonymous Pro

This commit contains font version 1.002
Merge pull request #1977 from rolandwalker/font_anonymous_pro

add monospace font Anonymous Pro
Fix documentation nits

Mostly this is spelling, capitalization, and whitespace.  One
substantive change is updating the list of fields given in FAQ.md
to match CONTRIBUTING.md.  Also incorporates suggestions from @NanoXD,
removing an old paragraph from FAQ.md re: nested containers.
Merge pull request #1985 from rolandwalker/doc_nits

Fix documentation nits
add Adobe fonts Source Code Pro, Source Sans Pro

These are released under SIL Open Font License. Included in this commit:
Source Code Pro version 1.017, Source Sans Pro version 1.050.
Merge pull request #1986 from rolandwalker/fonts_adobe_source

add Adobe fonts Source Code Pro, Source Sans Pro
add PT fonts

PT Mono in particular is useful for coders who use Cyrillic text.
Included in this commit: PT Mono v 1.002, PT Sans v 2.004,
PT Serif v 1.001.
Merge pull request #1988 from rolandwalker/font_pt_family

add PT fonts
add Ubuntu font family

Includes versions 0.80 of faces Ubuntu Mono, Ubuntu, Ubuntu Light,
Ubuntu Condensed
Merge pull request #1989 from rolandwalker/fonts_ubuntu

add Ubuntu font family
bugfix: kdiff3 cask name incorrect
Merge pull request #1990 from rolandwalker/kdiff3_bugfix

bugfix: kdiff3 cask name incorrect
Document conventions for fonts

Multiple faces rule per IRC with @phinze
Merge pull request #1991 from rolandwalker/font_doc

Document conventions for fonts
add GNU FreeFont family

This commit contains versions 0412.2268 of GNU FreeSans, FreeMono, and
FreeSerif.
Merge pull request #1996 from rolandwalker/gnu_freefont

add GNU FreeFont family
add font Code2000 and friends

This commmit includes Code2000 v1.171, Code2001 v0.919, Code2002 v0.917
add font Noto Sans

Noto Sans is a newish project by Google to provide a font covering all
languages. Version 1.04 included here.
add font Google Cousine

this commit includes version 1.21
add Red Hat Liberation font family

This commit includes versions 2.00.1 of Liberation Sans, Liberation Mono,
and Liberation Serif