improve documentation
improve documentation

gotomypc/qxmpp,olesalscheider/qxmpp,deepak899/qxmpp,Ilyatk/qxmpp,pol51/QXMPP-CMake,cccco/qxmpp,KangLin/qxmpp,gamenet/qxmpp_old,deepak899/qxmpp,projedi/qxmpp-ffmpeg,gamenet/qxmpp,ycsoft/qxmpp,gamenet/qxmpp,gamenet/qxmpp_old,ycsoft/qxmpp,cccco/qxmpp,trulabs/qxmpp-old,gamenet/qxmpp,deepak899/qxmpp,kollix/qxmpp,pol51/QXMPP-CMake,Kaffeine/qxmpp,gamenet/qxmpp_old,cccco/qxmpp,projedi/qxmpp-ffmpeg,olesalscheider/qxmpp,unisontech/qxmpp,ycsoft/qxmpp,gotomypc/qxmpp,unisontech/qxmpp,LightZam/qxmpp,olesalscheider/qxmpp,KangLin/qxmpp,gotomypc/qxmpp,unisontech/qxmpp,pol51/QXMPP-CMake,KangLin/qxmpp,kollix/qxmpp,LightZam/qxmpp,Kaffeine/qxmpp,kollix/qxmpp,Kaffeine/qxmpp,Ilyatk/qxmpp,trulabs/qxmpp-old,Ilyatk/qxmpp,LightZam/qxmpp,trulabs/qxmpp-old