changed error to warning
Merge branch 'master' of https://github.com/ufz/ogs
fixed nullptr check to addNeighbor method
simplified surface extraction method
removed duplicate methods for returning edge length
implemented calculation for edge length range inside mesh class
Removed obsolete CMake options for doxygen.

These options are automatically set to yes if dot was found.
Dot tool gets already searched when searching for doxygen.
Fixed order.
Fixed some doxygen warnings.
Merge pull request #323 from bilke/doxyfile-fix

Some fixes for Doxygen
Fixed a typo for collecting tpp-files for Visual Studio.
This correctly finds Doxygen with dot on Windows.

I also proposed a PR on CMake to integrate this directly:
https://github.com/Kitware/CMake/pull/91
Find the new Boost binary installers for Windows.

See
http://sourceforge.net/projects/boost/files/boost-binaries/1.55.0-build2
simplified edge length comparison
Merge branch 'master' of https://github.com/ufz/ogs into petsc_vector
Format the long comment in PETScVector
Correct a character in the long comment in PETScVector
Fix for finding eigen on Windows when installed devguide-like.
changed initial max value to negative double max