Add support for SQL databases

The goal of this branch is to add support for SQL databases using Anorm from the
Play framework.

This branch makes SQLite
the default storage mechanism. There are now no setup steps -- if you have Scala
2.9 installed and you download Zipkin, you can immediately run the daemons.
Documentation for getting other SQL databases running is in
`doc/sql-databases.md`.

Author: @IceCreamYou
Fixes #272
URL: https://github.com/twitter/zipkin/pull/272
fix a merge artifact that I'd missed
Minor syntactic changes

- Added a few missing semicolons
- Removed a repeated variable definition
- Used strict equality where applicable

Author: @AnSavvides
Fixes #280
URL: https://github.com/twitter/zipkin/pull/280
Fix Anorm storage incorrectly converts duration to String instead of Long when saving annotations
Dependency Visualizations

This is the final work to bubble up the aggregate dependencies to the frontend.

Author: @bmdhacks
Fixes #276
URL: https://github.com/twitter/zipkin/pull/276
update to latest dependencies

This is basically so I could get Time.fromMicroseconds() in util, but it pulled
a bunch of other stuff up too.

Author: @bmdhacks
Fixes #284
URL: https://github.com/twitter/zipkin/pull/284
Add HBase backend

* Added zipkin-hbase subproject
* Created HTableFactoryWithExecutor to create HTables with a thread pool.
* Create HBaseTable, an async facade on HTable.
* Created HBaseStorage
* HBase storage puts serialized thrift into the zipkin.storage table
* Created HBaseIndex
* Created HBaseAggregates
* add the ability to globally assign an id to a string in HBase.
* Add hbase command to query and collector
* Changed indexSpanDuration to return Future[Unit].
* Allow compression on table creation
* Speed up tests by limiting tables created.
* Code clean up.
* Cap HBase threads created.