Merge pull request #156 from ktakagaki/Constants

Constants
Filter kernel casting
Merge branch 'master' of https://github.com/scalanlp/breeze into filter1
ensure that operator implementations get loaded by making sure the companion object is initialized
Merge remote-tracking branch 'scalanlp/master'
weird ocmpile error...
Merge branch 'master' of https://github.com/scalanlp/breeze