* classify and sort the doxygen "related pages"

by tweaking the filename and adding 2 categories:
   Troubleshooting and Advanced
* use the EXCLUDE_SYMBOLS to clean the class list
  (insteaded of a homemade bash script)
* remove the broken "exemple list"
* re-structure the unsupported directory as mentionned in the ML and
  integrate the doc as follow:
  - snippets of the unsupported directory are directly imported from the
    main snippets/CMakefile.txt (no need to duplicate code)
  - add a top level "Unsupported modules" group
  - unsupported modules have to defined their own sub group and nest it
    using \ingroup Unsupported_modules
  - then a pair of //@{ //@} will put everything in the submodule
  - this is just a proposal !

disabled/buildexamplelist.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+echo "namespace Eigen {"
+echo "/** \page ExampleList"
+echo "<h1>Selected list of examples</h1>"
+
+grep \\addexample $1/Eigen/src/*/*.h -R | cut -d \\ -f 2- | \
+while read example;
+do
+anchor=`echo "$example" | cut -d " " -f 2`
+text=`echo "$example" | cut -d " " -f 4-`
+echo "\\\li \\\ref $anchor \"$text\""
+done
+echo "*/"
+echo "}"

disabled/cleanhierarchy.sh

@@ -0,0 +1,5 @@
+#!/bin/sh
+
+sed -i 's/^.li.*MatrixBase\&lt.*gt.*a.$/ /g' $1
+sed -i 's/^.li.*MapBase\&lt.*gt.*a.$/ /g' $1
+sed -i 's/^.li.*RotationBase\&lt.*gt.*a.$/ /g' $1