[doc] Add wheel and C extension info

doc/source/dev_work_with_source.rst

@@ -11,6 +11,20 @@ Directory           Python package   Description
 ``./library``       ``cadbiom``      Library used by the 2 previous packages
 ==================  ===============  =======================================
 
+All the code is developped in Python language.
+
+However some particularly costly functions in computation time have been written in C.
+These functions are included in an internal extension of the library.
+
+The extension is compiled during installation or directly downloaded without compiling if your
+system supports **Python wheels**.
+This is a *relatively new standard* for the distribution of Python packages
+available for Linux, Windows or macOS with ``pip >= 1.4`` and ``setuptools >= 0.8``.
+This system is a faster and secure way to install native C extension packages.
+
+.. seealso:: `https://pythonwheels.com/ <https://pythonwheels.com/>`_
+
+
 .. note::
    All existing modules belonging to the above packages
    is not (yet) fully described in the following technical documentation.

doc/source/installation.rst

@@ -22,7 +22,9 @@ without heavy design changes to GTK3 that is specific to Python 3.
 
 We use standard Python application packaging by hosting our program on the PyPI platform.
 This simple and light but well-proven system allows to quickly deploy and install an application.
-The procedure is described in the following chapter.
+The procedure is described in the next chapter.
+
+.. seealso:: `Working with Cadbiom source code <./dev_work_with_source.html#working-with-cadbiom-source-code>`_
 
 ..
    Veuillez noter que contrairement à des idées (trop) largement répandues, l'usage de containers