Update docs and version numbers for v2.0.0 release

[jmakhack]

Task Context

As the v2.0.0 issues are all nearing completion, this task is to prepare the docs and bump the version numbers for this release.

This issue is to be done after all the other v2.0.0 issues are complete.

[jmakhack]

Since v1.2.0 has been changed to v2.0.0 due to a good amount of major features being added, part of this work would also include going into the code and changing all the references to v1.2.0 to v2.0.0.

[jmakhack]

Note: As part of this task, the copyright year/info within the code also needs to be updated accordingly.