Set unit-e version to 0.1.0

[cornelius]

• Set version reported by the unit-e client to 0.1.0, the version of the first testnet release
• Set CLIENT_VERSION_IS_RELEASE to false to indicate that this is a pre-release
• Adapt warning message which is put out in the RPC interface for pre-releases
• Adapt version numbers for availability of wallet features to the new version number. There is no history of unit-e releases yet so set they all to the same version of the initial release.

This change might require removing an existing datadir as the change appears as it would require a wallet downgrade.

This part of #887.

[cornelius]

utACK https://github.com/dtr-org/unit-e/pull/945/commits/61ff9921dcdcb7b9f9a88ec68930d5b88ab44f9b for the update with the new genesis block

[Ruteri]

utACK 61ff9921dcdcb7b9f9a88ec68930d5b88ab44f9b for the whole pr