Changed help
fixed several memory leaks

And infinity loop in stanza_destroy_form().
added support of captcha in a MUC
fixed memory leaks in presence.c
Merge remote-tracking branch 'dmitry/captcha-2' into captcha
Moved stophe references in message send
Start chat session on /msg with no message parameter

fixes #173
Autocomplete /group add and /group remove contact paramater

closes #193
Show message when contact already in group
Show message when removing contact from group when not in group
Show messages on /group add and /group remove

closes #189
closes #190
Fixed roster tests
Moved /account, /prefs and /theme to settings commands
Renamed _cmd_set commands
Sorted command prototypes
Renamed commands array
Restructured help
Changed client type to 'console' as per http://xmpp.org/registrar/disco-categories.html#client
Changed help for /help command
Show current setting with settings commands

closes #139