Handle taxonomy terms as entities in vocabulary_terms.inc

Currently ctools\plugins\content_types\vocabulary_context\vocabulary_terms.inc handles the terms by connecting straight to the db.
This leads to some confusion if someone likes to use the power of the taxonomy term entity (e.g. in my case we use the title module to translate the term names).
The attached patch changes the way how taxonomy terms are load. First it fetches the tids from the db and then it loads the terms using taxonomy_term_load_multiple().
I don't use a EntityFieldQuery because the support for terms seems to be limited atm.: #1054162: Taxonomy bundles not supported by EntityFieldQuery (followup)