Make port in HttpServer configurable
SPARK-1174 Add port configuration for HttpFileServer

Uses spark.fileserver.port
SPARK-1176 Add port configuration for HttpBroadcast

Uses spark.broadcast.port
Add a configuration option for spark-shell's class server

spark.replClassServer.port
Make Spark's block manager port configurable

spark.blockManager.port
Fix ConnectionManager to retry with increment

Fails when running master+worker+executor+shell on the same machine.  I think
the issue is that both the shell and the executor attempt to start a
ConnectionManager, which causes port conflicts.  Solution is to attempt and
increment on BindExceptions
Add fallover increment logic for HttpServer
Fix up HttpServer port increments
Document new port configuration options

- spark.fileserver.port
- spark.broadcast.port
- spark.replClassServer.port
- spark.blockManager.port
Reformat for style checker
Remove type on val to match surrounding style
Unify port fallback logic to a single place
Fix style issue
Trust the server start function to report the port the service started on
Merge branch 'SPARK-2157' of github.com:ash211/spark into configure-ports
Move start service logic to Utils
Assorted fixes