Added section on MongoClient connection pooling
Fixes to test suite to pass the stricter max sizes for write commands
Merge pull request #1155 from chrischang12/mc-connection-pooling

Added section on MongoClient connection pooling
NODE-158 fix statistical strategy
Added tests for w:0 and some small fixes for merging results
Merge remote-tracking branch 'val/statistics-strategy' into 1.4
Fixes for write concerns correctly propegated through gridfs
Merged in 1.4