MeshLib add properties

This PR is based on the discussion in PR #531:
- It adds an implemention to manage properties within the Mesh.
- The properties are associated to specific mesh items like mesh nodes or mesh
  elements via an enum class (see enum class MeshItemType).
- The properties are not restricted to a particular data type, you can use several types like double, vector or matrix
  types at run time together (see tests).
- There is not a possibility to get the value data type.
I don't understand what you mean by "increasing dependency". 
Also, since C++11 there's also a ```std::shared_ptr``` - http://en.cppreference.com/w/cpp/memory/shared_ptr
(I haven't checked what - if any - differences there are between both implementations)