Major naming convention refactor.

To remove implication that these classes only use the CPU (There may be
a later distinction for CPU/GPU jobs):
ProcessorNode -> LocalNode (also in com.github.uberroot.ncjbot.api)
ProcessorJob -> LocalJob
RemoteProcessorJob -> RemoteJob
ProcessorJobEnvironment -> JobEnvironment

To prevent confusion between high-level and low-level networking:
NetworkManager -> OverlayManager (also in
com.github.uberroot.ncjbot.api)

To clarify meaning:
RemoteJob.source -> RemoteJob.remoteNode
RemoteJob.getSource() -> RemoteJob.getRemoteNode()
JobEnvironment.sourceJob -> JobEnvironment.parent