context 6.x-2.0-rc3

Hopefully a final release candidate, adds a 'default' context condition and some more help as well as some bug fixes.

Changes since DRUPAL-6--2-0-RC2:

• #780652 by FrankT: Fixed String issues in the help text.
• #780658 by FrankT and Steven Jones: Fix there may not be any themes active.
• #782102 by Steven Jones: Fixed Context block list only displaying manually created, static blocks. No drupal defaults, menu or views blocks.
• Add a bunch of advanced help.
• #780702 by Steven Jones: Move the taxonomy condition to context.module and make it configurable so that not all taxonomies show up in the list.
• #780172 by Steven Jones: Add a default context condition.
• Add 'Steven Jones' to the README as a maintainer.