Use master version3.xml for all future generation.

Merge pull request #192 from pmienk/version3

Update to maintain libbitcoin project in libbitcoin-system repository.

Various updates.

Add segregated witness and regtest, fixes.

Add bip68/112/113, network.invalid_services, optimizations.

Significant optimizations, consensus fix.

Various optimizations and fixes.

Major new features and improved quality.

Bump minor version number for minor release.

Bump minor version number for minor release.