Add possbility to tip random amount.
Add possbility to tip random amount.

Usage: !tip <user> random<amount>
framewr/node-tip-bot,Biersteker/node-tip-bot-twitter,Fuzzbawls/node-tip-bot,Biersteker/node-tip-bot-twitter,jwinterm/node-tip-bot,jwinterm/node-tip-bot,Fuzzbawls/node-tip-bot,framewr/node-tip-bot,unek/node-tip-bot,unek/node-tip-bot