Improvements towards new datasource remoting.

This commit includes upgrading to akka 2.2.1, updates to the dev subproject
to run under akka 2.2.1, as well as new changes to the Server actor infrastructure,
a new RemoteOperation wrapper operation, and a distribute() method on DataSourceLike.
Added RasterSource methods for +,-,*,/
Fix command line argument for dev project port.
Fixing subproject builds
Mark Cache as Serializable.
Upgrade Server cluster code and dev project for akka 2.2.1.
Merge pull request #593 from joshmarcus/topic/ds_remoting

Improvements towards new datasource remoting.
History now includes node identification information.

The History object now includes a string which identifies the node that
an operation was executed on, if a node has a default external address.

The toString() method will include the system id string, but has an optional
boolean argument to exclude it.
Merged in upstream, fixed tests.
Forward RemoteOperations at the dispatcher level.
Update dev/cluster client to use data sources.
Set default cluster configuration name.
Merge pull request #596 from joshmarcus/topic/node_history

History now includes node identification information.
Merge pull request #594 from lossyrob/localOpMethods

Added RasterSource methods for +,-,*,/
Merge branch 'master' of github.com:geotrellis/geotrellis into topic/distribute_data_sources
Created a CollectMap for Map[K,Op[V]] -> Map[K,V]
Merge pull request #598 from lossyrob/op/CollectMap

Created a CollectMap for Map[K,Op[V]] -> Map[K,V]
Minor README fixes.
Shutdown server in dev/cluster demo.
Include system name in Literal History objects.