* parallel.el (parallel--sentinel): Cleanup service when the server is
shutdown.
* parallel.el: Less closures, more plists.

Instead of using the lexical env to store the exec-fun, env, proc... Use
processes plist.
* parallel.el: Add docstrings and comments.
* parallel.el (parallel-start): Permit to customize the emacs used for the
remote call.
* test-parallel.el: Remove test- prefix.
* test-parallel.el: Remove lexical-binding (to test other version of Emacs).
* parallel.el (parallel-start): Be sure that server-service is a filename.
* parallel.el (parallel-start): Cleanup if something goes wrong with
processes.
* parallel.el (parallel-start): Add an option to select another library
for parallel-remote.
* test-parallel.el: Add tests.
* parallel.el: Rename option `no-batch' to `graphical'.
* parallel.el: Remove unnecessary `mode' as file variable.
* parallel.el: Strategy change: use symbol plist to store data instead of
processes and use only one server listening on the localhost (no more unix
socket).
* parallel.el: Cleanup at the end of a process.
* test-parallel.el: Add minor test
* parallel.el (parallel-start): Allow configuration through config.
(parallel--new-task): Enforce uniqueness of tasks.
* parallel.el (parallel--init-server parallel--get-task-process): Add
docstrings.
* parallel.el: Remove prefix "emacs-".
* parallel.el: Allow "true" remote execution. That is, execute code on a
remote host through SSH.
* parallel.el (parallel-start): `file-truename' doesn't work, as expected, through SSH.