Semantic Search

[Jazzpirate]

Should largely work out of the box using MathWebSearch, but we might need to figure out how to generate an index from FLOMDoc-XHTML, that maybe also makes use of semantic information?

(I notice that the word semantic is somewhat overlaoded here: Semantic serach in the sense of MathWebSearch operates on syntax trees only, so it's more syntactic search in the logical sense and only semantic in the sense of "syntax-tree aware")