Merge from vendor branch TNF:

Merge from vendor branch TNF:
Importing ruby-fssm package version 0.2.7.  It is needed by newer
ruby-compass pacakge.

The File System State Monitor keeps track of the state of any number
of paths and will fire events when said state changes
(create/update/delete). FSSM supports using FSEvents on MacOS, Inotify
on GNU/Linux, and polling anywhere else.