new faster SVN plugin
Report the SVN need upgrade

This happen when subversion 1.7+ is used on a repository created with subversion up to 1.6
Inline `parse_svn` to avoid leaky state

As noted in review, `in_svn` is not properly reset to false. This is better anyway to not leak state.
Heavy refactor of svn-fast-info
Added further cleanup and svn status information
Renamed the methods of this script
Renames main plugin function to `svn_prompt_info`
Merge pull request #2400 from bric3/svn_fast_plugin

new faster SVN plugin