Handle spaces in graphite metric names

Spaces in metric names get replaced by underscore
Ignore and log malformed messages
Merge pull request #339 from pyr/feature-atomization

Switch more streams from refs to atoms
Merge pull request #335 from sblask/fix-for-graphite-messages-containing-spaces

Handle spaces in graphite metric names
streams/rollup: test single single event per interval
Added OpenTSDB plugin
Graphite server: improve error handling.

Also improvements to tests, performance, modularity, removed dependency
on core.match, etc. Possibly fixes #338?
Uncomment integration test
Merge pull request #340 from pradeepchhetri/master

Added OpenTSDB plugin
atomize deps tests
atomize fold-interval
atomize fill-in
atomize fill-in-last
atomize interpolate-constant
atomize ddt-events
atomize by-fn and by extension by