Update README.md w/ brief hardfork overview
Update README.md w/ brief hardfork overview

*Hardfork #1 [Block 75,888+]
 - ETA: Monday, May 26, 2014 @ 8:08 AM (UTC)
 - Difficulty adjusts after every block using a weighted calculation
 - Bonus blocks and standard blocks are averaged together to create steady 188 coin blocks (distribution and total coins remain unaffected).
octocoin/octocoin,octocoin/octocoin,octocoin/octocoin,octocoin/octocoin,octocoin/octocoin,octocoin/octocoin,octocoin/octocoin,octocoin/octocoin