Remove duplicates from library root.

Closes #708
docs: Add Mopify to web client list
docs: Update APT and AUR instructions
docs: Recommend our Homebrew tap for OS X installs
docs: Split install docs into four pages
docs: Link directly to the right install page
Tornado redefines '::' to IPv6 only, so set '::' to None to get expected behaviour

Signed-off-by: Lasse Bigum <lasse@bigum.org>
Merge pull request #770 from ZenithDK/fix/hostname_colon

Tornado redefines '::' to IPv6 only, so set '::' to None to get expected...
Check configured static_dir and fall back to default if non-existing

Signed-off-by: Lasse Bigum <lasse@bigum.org>
docs: Fix typos
Remove 'mad' from 'mopidy deps' listing

The 'lame' element does the same job, and is preferable since mad is GPL
licensed.
Merge branch 'ZenithDK/fix/check_static_dir' into develop
http: Style tweaks
Merge 'dz0ny/bug/fix-708-duplicate' into develop
core: Use a set to get unique dirs, and sorted to make the output stable
Add fabric to dev-requirements.txt
docs: OS X install requires XQuartz
mixer: Add mixer API
docs: Add Mopidy-ALSAMixer to mixer impl list
mixer: Add name attr to mixer API