Extract AssemblerLib::MeshComponentMap code.

Add AssemblerLib dir to test cmake file and to doxygen.
The code was also reformatted and documented more properly.

Remove delegating constructor for Line.
Use typedef instead of c++11 using directive.
MeshComponentMap: Remove not required header. Use nop. Correct doc.
Disable implicit conversion from Location to Line.
In TestMeshComponentMap: correct comment.