Upgrade to grunt-jquery-content 0.10.1.
class-animation-desc.xml: minor rewording
Category: Get pages and entries/posts of a category by parsing its script tag's JSON manifest

- Use elementtree instead of libxmljs, latter is overkill and former
  installation is simpler (requires no compilation step);
Category: Augment error with filename information
Category: sanitize html for xml parse
Generate categories.json manifest file