Update source code references to add git and re-wrap
Update plugins section of manual

• Merge extra plugins section, since they're all provided now.
• Synchronize list of plugins with website list.
• Add new “Obsolete plugins” section for the ones we're not
  shipping anymore for a variety of reasons.
Fix typo
Fix diff format detection.

When '-p' option is used ' @@' can be followed by function name.
Add coloring of diff patches inside emails.