PPCoin: Update development README and a few minor text message updates.
        Includes courtesy super3 (#20) and brossi (#22).
PPCoin: Update subversion format to include ppcoin version based on BIP 14
PPCoin: Update main net client icon with the standard icon
PPCoin: Update windows setup file icon
PPCoin: Update dns seeds and pnSeed
PPCoin: v0.4 protocol change
  - stake modifier protocol adjustment for possible future p2pool support
  - stake modifier protocol bug fix to maintain fixed generation interval
  - network protocol version updated
  - upgrade timestamp recorded in txdb and message for late upgrades
Upgrade requirement:
  Mandatory.
  Must upgrade before May 5, 2014.
  Testnet upgrade before March 24, 2014.
  Redownload of blockchain is not required for the upgrade.
  Late upgrades close to or after deadline require redownload of blockchain.
PPCoin: add hardened checkpoint for v0.4.0 release
PPCoin: Update client version to 0.4.0
PPCoin: Update version from release candidate to 0.4.0 release
        Update COPYING and About dialog
        Switch Windows installer icon
merging 0.4 release