(PDB-605) Prepare all documentation headers for 2.0 release

This changes all the documentation headers for each markdown file to reflect
the upcoming 2.0 release.

Signed-off-by: Ken Barber <ken@bob.sh>
(PDB-605) Revert some 1.6->2.0 changes

Some files had 1.6 converted to 2.0 erroneously. This fixes up those mistakes.

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #952 from kbarber/ticket/master/pdb-605-update-documentation-headers-for-200

(PDB-605) Prepare all documentation headers for 2.0 release