#293 Slow Processing of Galago RM3 Feedback Models

[Lemur Project]

An issue concerning retrieval speed with Galago RM3 query expansion has been reported by
serveral users.

RM3 is reported as slow on several data sets, taking 14 seconds to answer RM3 queries using
feedback parameters fbDocs=5 and fbTerm=100, compared to 0.6 second for #combine.

Search times are even longer using the following data set:
https://s3.amazonaws.com/RemoteDisk/TextCollections/StackExchange/StackOverflowTrectext/output_trectext.tar.gz

Possibly the problem stems from inefficently invoked custom user code, but time comparisons
need to be made using standard galago batch-search, to confirm a problem with processing
efficiency.