merge with crew

hgweb: rename 'currentbaseline' template keyword to 'basenode' Shorter and clearer. This keyword represents the node we're currently diffing against.

hgweb: rename 'changesetbaseline' template to 'difffrom' More accurately reflects what it will be used for, and is also shorter. This template is used to change which rev the current rev is diff'd against. For example, if you're at '/rev/P1:REV', this would link to a path like '/rev/P2:REV'. Example usage in a template: {parent%difffrom}