Update block version to 1

[MaciejBaj]

While 0.9.16 and 1.0. versions are not compatible with each other (peers cannot connect) - there is still possible to keep the 0.9.16 chain running. Because there is nothing at stake - probably most of the delegates would like to keep forging on that chain, and because of such a possibility - it's reasonable to assume that 0.9.16 chain will be the longer one. There can be some issues if somebody decide to migrate 0.9.16 chain later (after migration height) and announce it to rest of the peers that are already running 1.0.0 chain. To ensure smooth migration and prevent situation described above from happening - would be nice to bump block's property version (which is taken into account when generating the signature).