Merge from vendor branch TNF:

Merge from vendor branch TNF:
Initial import of py-Whoosh-0.1.13:

Whoosh is a fast, featureful full-text indexing and searching
library implemented in pure Python.

Some of Whoosh's features include:

    * Pythonic API.
    * Pure-Python. No compilation or binary packages needed, no
    mysterious crashes.
    * Fielded indexing and search.
    * Fast indexing and retrieval -- much faster than any other
    pure-Python solution.
    * Pluggable scoring algorithm (including BM25F), text analysis,
    storage, posting format, etc.
    * Powerful query language parsed by pyparsing.
    * Pure Python spell-checker (as far as I know, the only one).

Whoosh takes much inspiration (and sometimes translates code) from
other open-source search engines. The fundamental design is similar
to (but does not entirely work like and is not compatible with)
Lucene, but uses KinoSearch's indexing algorithm, some scoring
algorithms from Terrier, and the English morphological variation
generator from Minion.