Added tests for class AABB containing points with only negative coordinates.
GeoLib::AABB: Init min and max using first point.
GeoLib::AABB: Init the max point with invalid data in init list.
Merge pull request #168 from TomFischer/BugFixAxisAlignedBoundingBox

Bug fix for axis aligned bounding box class AABB.
Speed up Mesh::removeUnusedMeshNodes() a bit.
Merge pull request #169 from TomFischer/AccelerateMeshRemoveUnusedMeshNodes

Speed up Mesh::removeUnusedMeshNodes() a bit.
Update Doxyfile.in to 1.8.4 version.

Updated with 'doxygen -u'.
Merge pull request #167 from endJunction/DoxygenUpdate

Update Doxyfile.in to 1.8.4 version.
Testing with and without Gui on travis.
Typo.
Merge pull request #174 from bilke/travis-multiple-builds

Testing multiple build runs on travis.
Merge remote-tracking branch 'origin/master' into vtk6

Conflicts:
	.travis.yml
Added CMake option OGS_SYSTEM_VTK_ONLY to prevent building Vtk locally.