Add GPL header
Add a basic file on dual licenses
Rename LEGAL to LEGAL.md
Added a basic file on dual licenses
Spell check
Possibly fixed the issue that group chats would sometimes DOS themselves.
Adjusted some delays.

Decreased LAN discovery packet sending interval.

Attempted fix of the everyone is unknown bug in group chats.
This should install vpx
Replaced magic numbers inside candidates_create_internal() with enumerated list
astyled last commit.
Updated TODO.
Changed libtoxcore_la_LDADD to libtoxcore_la_LIBADD cause of creating a library.
Fixed test issue.