Merge pull request #124 from Schlumpf/master

Fix smiley selection
Use tox_do_interval
Adapted to toxcore changes
Linked to toxav
Added message splitting
It looks for a space, dot, comma or a hyphen near the end of a message (in its
last 1/4th byte-wise) and splits on those. If non of those are found, it splits
the message right before a start of the last fully or partially fitting into
TOX_MAX_MESSAGE_LENGTH codepoint.
Fixed Travis
Fixed toxav static linking for Windows