checkpoint added.

 - note: client update being worked on within "dev" branch. (no
   mandatory update though). Will progressively move up to our release
   and master branches upon completion / successful testing.
Merge branch 'master' into release-0.1.3
release-0.1.3 branch and non-official build
Merge branch 'release-0.1.3' into dev-0.1.3
testnet update with smaller retarget limits and new alert key.

 - new ecdsa keypair for testnet.
 - testnet seednodes updated.
 - smaller testnet retarget limits.
Merge branch 'dev-0.1.3' into release-0.1.3
Merge branch 'release-0.1.3'
master branch & unstable client warning removal
0.1.3-49 changelog
fixes issue #10
Merge branch 'dev-0.1.3' into release-0.1.3
Merge branch 'release-0.1.3'
alerts: mainnet key update

 - mainnet ecdsa keypair updated to prevent abuse from previous
   owner(s).
 - client version set to 0.8.0.1 ("/SatoshiClone:0.8.0.1/")
Merge branch 'dev-0.1.3' into release-0.1.3
Merge branch 'release-0.1.3'

 - new ecdsa public key ; prevent abuse from previous owner(s). Will be used to announce important informations to users (mandatory updates, ...)
 - client version bumped to 0.8.0.1
build script version bump
changelog update
Merge branch 'master' into release-0.1.3
release branch ; unstable flag
Merge branch 'release-0.1.3' into dev-0.1.3