Updated cross-compile instructions
Merge branch 'update-crosscompile-instructions' of https://github.com/nurupo/InsertProjectNameHere
Added some checks to mutex related functions.
ifdef out use of linux/limts.h in test_avatars

This fixes building on OS X and other systems whose limits.hs have PATH_MAX.
housekeeping
Merge branch 'stal888-patch-1'
remove tox_avatar_hash
Update documentation after API changes

Commit ba6ae15a739257200b04a10b6ecd22fe210951e1 introduced some API
changes, update the documentation to reflect them.
Merge branch 'dubslow-housekeeping-docs' of https://github.com/ittner/toxcore
Merge branch 'master' of https://github.com/dubslow/toxcore
Tox object doesn't need to be passed to tox_hash.
Some code written for new group chats.
Removed groupchats from core.
Removed now useless atributes from structs.
Update avatar documentation

Update the documentation to reflect the API changes introduced by
commits 21be438b2b3f7aa1b65b76a7f528eacfe5b634db and
d409bad30dd1657f6b54ea5e38a4d9155f718ae1
More groupchats code written.
Group chats are starting to work.
add API function to unset avatar
DHT can now be used for group chat cons and friend cons at the same time.
Wrote more new groupchats code.