erlang: avoid creating an extra fun when calling spawn_link.

This commit replaces some of spawn_link(Fun) and spawn_link(Node, Fun) with
spawn_link(Module, Function, Args) and spawn_link(Node, Module, Function, Args)
respectively.  The latter forms are prefered because of their simplicity.
Merge pull request #511 from pooya/new_spawn

erlang: avoid creating an extra fun when calling spawn_link.
worker_runtime: allow sending "more" in inputs.

The runtime used to tell the worker that there is no more inputs in all of the
cases.  In the new model, the runtime will tell the worker that there is more
inputs in case there is more inputs to come.

At the moemnt, the runtime has all of the inputs when the task starts but this
will change with the concurrent stages.