Add folsom as a dependency.
Simplify the implementation of two functions.
Start folsom on the slave nodes.
Add folsomite for exporting profiles.

Folsomite needs a remote graphite server.  It will be disabled by
default.
Add profiling to some functions in disco and ddfs.
Merge pull request #435 from pooya/shayan/folsomite

Shayan/folsomite