zipkin storm: kafka spout and span scheme

This is to pave the way for zipkin storm jobs. A new project zipkin-storm is
created to contain all the storm related sources. This pull request includes:
1.
span scheme to parse the steam data
2. kafka spout to reading data from kafka
queue
3. sbt changes to create standalone jar "zipkin-storm" for storm job
submission.

Author: @suchang
Fixes #326
URL: https://github.com/twitter/zipkin/pull/326
fix merge conflicts
implement semigroup instead of monaid for Dependencyies
revert back to use monoid
Merge pull request #340 from suchang/fix-dependency-scalding-job

Bump Algebird version to 0.4.0