Merge pull request #284 from rrthomas/master

Make metapolator npm installable (fixes #189)
add socket.io based file system events
Merge pull request #282 from graphicore/file-system-monitoring

add socket.io based file system events
bugfix: add slash to pathPrefix argument
Merge pull request #286 from graphicore/bugfix-socket-file-prefix

bugfix: add slash to pathPrefix argument
bugfix: a typo prevented proper filtering
Merge pull request #288 from graphicore/bugfix-selectorEngine

bugfix: a typo prevented proper filtering