Initial commit of twitter nexus scheduler.
Adding basic configuration options and parsing to the scheduler.
Nexus: Additional development on the twitter scheduler.
Nexus: Initial checkin of nexus python client.
Nexus: Refactor of scheduler.
Nexus: Added a rudimentary work queue for relaying commands received via thrift.
Nexus: More work on SchedulerCore and SchedulerHub, reorganized internal data structures.
Nexus: Change ScheduleStatus to mirror TaskState in nexus core.
scheduler changes & real executor
Changed some overloaded terminology
Changed Executor from Guiced -> InjectableMain, more Guice...
Nexus, executor running with a sample java-jar
Renamed a property
Small nexus scheduler bug fixes.
Merge branch 'nexus_scheduler' of http://git.local.twitter.com/science into nexus_scheduler

Conflicts:
	nexus/thrift/nexus_twitter.thrift
	src/java/com/twitter/nexus/scheduler/SchedulerHub.java
Removing unnecessary thrift object.
Getting rid of concrete/non-concrete thrift types.
Nexus: Moderate scheduler refactor
Nexus: Launch scheduler on ephemeral port, advertise via zookeeper
Nexus: Changing scheduler thrift interface to require job owner on some methods.
Nexus: Adding HTTP handlers to provide info about configured jobs.
Nexus: Simplified thrift interface to use query objects.
Nexus: Implemented HTTP interface for scheduler.
Nexus: Implemented cron-based scheduling.
Nexus: Fix - SchedulerCore was not passing kill command to scheduler modules.
Nexus: Add display for cron job next run in HTTP interface.