Added warning about blocking in the morehelp for cvsup.
Added warning about blocking in the morehelp for cvsup.

mazaclub/mazabot-core,buildbot/supybot,prashantpawar/supybot-rothbot,ProgVal/Limnoria-test,Ban3/Limnoria,ProgVal/Limnoria-test,mazaclub/mazabot-core,jeffmahoney/supybot,kblin/supybot-gsoc,raboof/supybot,Ban3/Limnoria,haxwithaxe/supybot,frumiousbandersnatch/supybot-code