MDLSITE-2009 Implement on-demand & on-sync types

They only apply to master branch.

- Custom commit messages.
- on-demand advances to current date.
- on-sync increments +1.00
- commented some code that caused master version
  to become out of sync after major release (violating on-sync)
  that needs to be changed to something else only modifying $release.
- TODO: Ensure that on-demand happens only in beta & rc status.
- TODO: Ensure that on-sync happens only in dev status.