Merge pull request #50 from vvidal/master

Gharial now ok under windows and macos (test just now), so,
fix cmake (xerces)
Fixing Observer and Observable dependency.
Merge pull request #51 from ruribe/master

Restablishing Observer and Observable dependency
Add a Manifold/cube.off and a NonManifold/cubeNonMan.off useful for testing.
new simple meshes for testing.
minor modifications on Remeshing/RemeshingBaseOperations.h and LaplacianSmoothingMeshFilter.h
Add Data directory dependency (in a generic way) for easier testing.