adding some simple matrix element filtering
fixing remove cols by method
removing from readme
Merge remote-tracking branch 'upstream/develop' into develop
adding myself back into the readme
Fix keepColsBy by passing RowVector
Merge pull request #423 from jattenberg/develop

Merge #423
Merge pull request #439 from reconditesea/klin_fix_keepColsBy

Fix keepColsBy by passing RowVector
Add support for Product for converting from CTuple
Merge pull request #441 from twitter/product-converter

Merge #441