Handle spaces in graphite metric names

Spaces in metric names get replaced by underscore
Ignore and log malformed messages
atomize part-time-fast-interval
atomize sum-over-time
atomize mean-over-time
atomize register and append
update core test for new append and register

update core test for new append and register
update streams test for append and register
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