Fix segfault (checking for prev block of genesis).
Merge darksend v11 updates.
revert 4f95ea2: testnet v4
Merge upstream commits of branch 'v0.11.0.x' of darkcoin/darkcoin into devel-0.9
Merge pull request #83 from vertoe/devel-0.9

Clean testnet reset to v3. (branch v11)