Offer solution for "error while loading shared libraries: libtoxcore.so.0: cannot open shared object file: No such file or directory".

Offer solution for "error while loading shared libraries: libtoxcore.so.0: cannot open shared object file: No such file or directory".
Merge pull request #636 from fr0stycl34r/patch-1

Offer solution for "error while loading shared libraries: libtoxcore.so....
Updated hardening doc.
Merge branch 'master' of https://github.com/irungentoo/ProjectTox-Core
Update av_api.md
Update av_api.md
Update av_api.md

add some code blocks in the markup
Update av_api.md

add some more shiny stuff
Update av_api.md

and some more
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that looks better :)
Update av_api.md

some markup was fucked up :P
Update av_api.md

forgot one paragraph
Merge pull request #637 from blackwolf12333/master

Make the av_api.md look a bit better
Fixed possible issue.
The group chats we invite a friend to are now stored.
Send ping packets in group chats every 30 seconds.
Auto delete inactive peers in the group chat.
addto_lists(): store the IP/Port that was used to *send*.

Avoids a DOS of sending a copy of a valid response with an invalid IP.
Behind #define LOGGING: Correct usage of now() to replacement unix_time().
Reduce duplicate data. Add a mostly empty skeleton test.