Handle timestamp incremental replication

[mjsqu]

Fixes #86

TIMESTAMP is a misleading column data type name in SQL Server - it has no equivalent date/time value

• Timestamp columns are treated as strings (e.g. 00000000000007d2)
• Convert VARBINARY/BIGINT is used to read in a held state value and compare it to a value in the synced table
• Tests added to show that incremental replication is working
• Redundant logic removed from existing incremental tests

[s7clarke10]

Thank you for preparing this change. Can we please update the following files. It will be required for the CI to push a change into PyPI.

• .bumpversion.cfg - update the release number
• pyproject.toml - update the release number
• CHANGELOG.md - Add release notes against the release number.