AZK-109 Add a new property for epoch millis.

Adds azkaban.flow.start.epoch.milliseconds.  Also consolidates code for
generating these props so it doesn't need to be added twice.
Support for foward dependencies in Azkaban. This patch enables users to have a construct like 'followedby=job1,job2' in their job configration when describing job flow. This works alongside the usual 'dependencies=job3,job4' construct. In fact, the implementation simply converts the followedby expression to its equivalent dependency expression. The goal is to enable users to describe job flow in a bi-directional manner, and might make it easier to reason about how jobs are pipelined together
Merge pull request #11 from jcrobak/AZK-109-epoch-millis

AZK-109 Add a new property for epoch millis.
Merge pull request #12 from azreda/master

Support for describing foward dependencies in Azkaban
direct to the new project site