Vector: add undocumented but required self.encoders field
add imports for Vector*Encoder
add imports to MultiEncoder
add PassThru to init
Merge branch 'master' into vector
Ping Travis
Merge pull request #443 from breznak/vector

small fixes for Vector
Include notice re: pip 1.5 changes
Merge pull request #537 from oxtopus/pip-fix

Include notice re: pip 1.5 changes
Merge branch 'master' of https://github.com/numenta/nupic