Remove information on 3.0 to 3.1 template upgrade

Add links to the information on the 2.0=>3.0 and 3.0=>3.1 upgrades.
Combine upgrade notes for 2.0=>3.0 and 3.0=>3.1
Add years of the older template versions for clarity
Add comma
Merge pull request #560 from saltybeagle/4.0_upgrading_docs

Add info on the Dreamweaver upgrade process for 3.1 to 4.0