message checksum between nodes with 0.2.9 or higher,
optimization level up from -O0 to -O2,
rpc functions: setlabel, getlabel, getaddressesbylabel, getreceivedbyaddress, getreceivedbylabel, listreceivedbyaddress, listreceivedbylabel
 -- version 0.2.9

git-svn-id: https://bitcoin.svn.sourceforge.net/svnroot/bitcoin/trunk@78 1a98c847-1fd6-4fd8-948a-caf3550aa51b