drush 6.x-3.2

Changes since DRUPAL-6--3-1:

• Backport --html option for help command.
• #875196 by omega8cc. The URL for DRUSH_TABLE_URL has changed because they switched to svn.
• #831272 by greg.1.anderson. '@sites' alias doesn't work unless drush can find at least one local site at the drupal root
• #820514 by greg.1.anderson. some commands (like sql-sync) wont respect ssh-options/ssh-port of sitealias
• #827404 by acrollet. drush up drupal does not preserve custom profiles.
• #836910 by moshe weitzman. drush_drupal_version() is broken on d7
• #850472 by tostinni. Add precisions to Windows README's install steps
• #838684 by dereine. allow drush_prompt to be optional.