Added necessary define when using GLUT.
Merge commit '844c66d7c29d67baf10b9aaa4a77feb51292d16d'
Updated copyright to 2013.
OGS_NO_EXTERNAL_LIBS only omits searching for libraries now.

Before also necessary tools were not searched for.
Fixed link on front page README.md

replaced ufz.github.com with
devguide.opengeosys.org
Merge pull request #72 from mylese/fixlink

Fixed link on front page README.md