SciDAVis - Improvements SVN-temp

Add missing ellipses to some menu items opening dialogs.

Closes bug #2989978 (File menu items (open, print etc) need ellipses).

Export table to TeX (patch #3082921 by Iurie Nistor)

Fix bug #2990172 (Axis label disappear permanently if 'Show Label' is disabled)

- Documented matrix mass-update methods just added to Python API.

- Added methods for mass-updating matrix cells to Python API.

- Fixed indentation of program listings broken by previous reorganization

- Added <sect2>'s to .adp file, mainly with an eye on the huge Python API
reference section.
- Added some missing sect2 id attributes.

- Split scripting chapter into separate muParser (formulas) and Python
(scripting) chapters. Explicitly introduces tutorial and reference sections
in the Python chapter.
- Polished somed details (separator char of keywords in .adp file, removed
reference to liborigin etc.)

- Renamed import script to opj2sciprj.py in order to more clearly reflect its purpose.

- Added generation of Qt Assistant .adp files for XSL-based conversion to HTML.