Merge branch 'release-0.1.3' into dev-0.1.3
Merge branch 'release-0.1.3' into dev-0.1.3
Merge branch 'release-0.1.3' into dev-0.1.3
Merge branch 'release-0.1.3' into dev-0.1.3
testnet: restored simple retargetting mechanism.

 - invalidates previous  testnet blocks
 - testnet checkpoints updated
 - testnet seednodes updated.
testnet: switch to simple retargetting.

 - note that testnet uses really small windows for computing new target.
   this may be cheated, but livenet will use longer windows preventing
   this.
testnet: switched back to a bitcoin-like retargetting window.
comments and logging.
checkpoint added.
logging
testnet: last ema attempt

 - new targets now limited to 1% change max
 - now measures individual block duration over last N blocks (90 for
   testnet)
 - averaged input data reduced to +/- 10% (108/120/132) ; should allow
   faster adjustments over time, by reducing "waves" height, especially
   when combined with above pre-averaging.
testnet: averaged block range timespan.

 - quick & dirty push for remote tester
testnet: fixed default value for blockrange in a rare case.
testnet: typo
logging.
upcoming livenet retargetting: better values.

 - smaller increments between sub-retargets.
testnet: allow longer blocks before reset.
Merge branch 'dev-0.1.3' into release-0.1.3