Make Matlab recognize ET as "supplemental software" with its own documentation just like MPT 3.1

[pgagarinov]

Assuming ET is installed If we look at help browser we see that Matlab recognizes MPT 3.1 as supplemental software. Authors of MPT has made this possible by following the instructions from http://www.mathworks.com/help/matlab/matlab_prog/display-custom-documentation.html

Right now we have elltool.doc.run_helpcollector utility that scans help header for all classes and functions in ET and produces doc\chap_functions.rst. This file is in reStructured text format but it was only meant to be part of ET manual document, not interactive help. We use Sphinx to convert rst files into latex and html (there is a page in Wiki that describes how we do it).

We need to improve run_helpheader so that it produces rst that can then produce html (via Sphinx) which is much more suitable for an interactive help viewable from Matlab Help Browser. If reStructured format is too limiting - we can create a special version of run_helpheader that generates html directly (though a preferrable solution we be using rst as an intermediate format.

For functions that that produce pictures we need to write scripts (a few for each function) that demonstrate a few use cases. run_helpheader would run those scripts automatically and capture pictures (the same way it does run demo examples and generate pictures for the manual). Those pictures would then become a part of interactive help.

Once html documentation is generate we need to follow all the steps from
http://www.mathworks.com/help/matlab/matlab_prog/display-custom-documentation.html
to integrate ET into Matlab. This way Matlab will recognize ET as "supplemental software".