"Mined" to "Minted" for StakeMint transactions & Readme update

I am a noob so this could be completely wrong and not work. As noted in this reddit thread it makes more sense to say "Minted": http://www.reddit.com/r/MintCoin/comments/22818m/mint_wallet_mining_by_itself_wtf_is_going_on/

Also Readme update with fixed markup and PoW removal info.