Merge pull request #183 from mannol1/master

Fixes problems with upstream changes
delete subwindows before parent window on resize to prevent memory leaks
create dns loopup threads in detached state & add a few missing error descriptions
use full name for log
change tab names:  prompt = home, friends = contacts
add buffer yanking, clean up input functions
fix undefined behaviour with string literals
another UB fix
increase max friends
small fix
cleanup/error checks
auto-completion for paths when sending file & improved auto-complete algorithm to do partial matches
return correct value, fix comment
autocomplete pathnames with spaces
print multiple matches for all tab-complete operations, fix bug when tab-completing at end of line
Added sounds
Added sound notifications and prepared for later system notifications. Also, now using libconfig for configuration loading.