Include RPyC tutorial into the docs (#237)

* Include RPyC tutorial into the docs

Author: ddemidov

docs/index.rst

@@ -11,6 +11,7 @@
    :maxdepth: 3
 
    spec
+   rpyc
 
 Indices and tables
 ==================

docs/rpyc.rst

@@ -0,0 +1,64 @@
+Working with ev3dev remotely using RPyC
+=======================================
+
+RPyC_ (pronounced as are-pie-see), or Remote Python Call, is a transparent
+python library for symmetrical remote procedure calls, clustering and
+distributed-computing. RPyC makes use of object-proxying, a technique that
+employs python’s dynamic nature, to overcome the physical boundaries between
+processes and computers, so that remote objects can be manipulated as if they
+were local. Here are simple steps you need to follow in order to install and
+use RPyC with ev3dev:
+
+1. Install RPyC both on the EV3 and on your desktop PC with the following
+   command (depending on your operating system, you may need to use ``pip3`` or
+   ``pip`` on the PC instead of ``easy_install3``):
+
+   .. code-block:: shell
+
+       sudo easy_install3 rpyc
+
+2. Create file ``rpyc_server.sh`` with the following contents on the EV3:
+
+   .. code-block:: shell
+
+      #!/bin/bash
+      python3 `which rpyc_classic.py`
+
+   and make the file executable:
+
+   .. code-block:: shell
+
+      chmod +x rpyc_classic.py
+
+   Launch the created file either from ssh session, or from brickman.
+
+3. Now you are ready to connect to the RPyC server from your desktop PC:
+
+   .. code-block:: py
+
+       import rpyc
+       conn = rpyc.classic.connect('ev3dev') # host name or IP address of the EV3
+       ev3 = conn.modules['ev3dev.ev3']      # import ev3dev.ev3 remotely
+       m = ev3.LargeMotor('outA')
+       m.run_timed(time_sp=1000, speed_sp=600)
+
+You can run scripts like this from any interactive python environment, like
+ipython shell/notebook, spyder, pycharm, etc.
+
+Some *advantages* of using RPyC with ev3dev are:
+
+* It uses much less resources than running ipython notebook on EV3; RPyC server
+  is lightweight, and only requires an IP connection to the EV3 once set up (no
+  ssh required).
+* The scripts you are working with are actually stored and edited on your
+  desktop PC, with your favorite editor/IDE.
+* Some robots may need much more computational power than what EV3 can give
+  you. A notable example is the Rubics cube solver: there is an algorithm that
+  provides almost optimal solution (in terms of number of cube rotations), but
+  it takes more RAM than is available on EV3. With RPYC, you could run the
+  heavy-duty computations on your desktop.
+
+The most obvious *disadvantage* is latency introduced by network connection.
+This may be a show stopper for robots where reaction speed is essential.
+
+.. _RPyC: http://rpyc.readthedocs.io/