Big changes in Eigen documentation:

- Organize the documentation into "chapters".
  - Each chapter include many documentation pages, reference pages organized as modules, and a quick reference page.
  - The "Chapters" tree is created using the defgroup/ingroup mechanism, even for the documentation pages (i.e., .dox files for which I added an \eigenManualPage macro that we can switch between \page or \defgroup ).
  - Add a "General topics" entry for all pages that do not fit well in the previous "chapters".
  - The highlevel struture is managed by a new eigendoxy_layout.xml file.
- remove the "index" and quite useless pages (namespace list, class hierarchy, member list, file list, etc.)
- add the javascript search-engine.
- add the "treeview" panel.
- remove \tableofcontents (replace them by a custom \eigenAutoToc macro to be able to easily re-enable if needed).
- add javascript to automatically generate a TOC from the h1/h2 tags of the current page, and put the TOC in the left side panel.
- overload various javascript function generated by doxygen to:
  - remove the root of the treeview
  - remove links to section/subsection from the treeview
  - automatically expand the "Chapters" section
  - automatically expand the current section
  - adjust the height of the treeview to take into account the TOC
- always use the default .css file, eigendoxy.css now only includes our modifications
- use Doxyfile to specify our logo
- remove cross references to unsupported modules (temporarily)

doc/C04_TutorialBlockOperations.dox

@@ -1,7 +1,6 @@
 namespace Eigen {
 
-/** \page TutorialBlockOperations Tutorial page 4 - %Block operations
-    \ingroup Tutorial
+/** \eigenManualPage TutorialBlockOperations Block operations
 
 \li \b Previous: \ref TutorialArrayClass
 \li \b Next: \ref TutorialAdvancedInitialization
@@ -11,7 +10,7 @@ A block is a rectangular part of a matrix or array. Blocks expressions can be us
 as rvalues and as lvalues. As usual with Eigen expressions, this abstraction has zero runtime cost
 provided that you let your compiler optimize.
 
-\tableofcontents
+\eigenAutoToc
 
 \section TutorialBlockOperationsUsing Using block operations