Install all headers

[josephmckenna]

Install all headers in cmake build

mkdir build
cd build
cmake ../
make
make install

Put headers into their own sub folder, so that headers will not conflict if users install the into /usr/local

[100%] Built target cadmesh
Install the project...
-- Install configuration: "Release"
-- Up-to-date: /usr/local/lib/cmake/cadmesh-2.0.0/cadmesh-config.cmake
-- Up-to-date: /usr/local/include/CADMesh/ASSIMPReader.hh
-- Up-to-date: /usr/local/include/CADMesh/BuiltInReader.hh
-- Up-to-date: /usr/local/include/CADMesh/CADMesh.hh
-- Up-to-date: /usr/local/include/CADMesh/CADMeshTemplate.hh
-- Up-to-date: /usr/local/include/CADMesh/Exceptions.hh
-- Up-to-date: /usr/local/include/CADMesh/FileTypes.hh
-- Up-to-date: /usr/local/include/CADMesh/Lexer.hh
-- Up-to-date: /usr/local/include/CADMesh/LexerMacros.hh
-- Up-to-date: /usr/local/include/CADMesh/Mesh.hh
-- Up-to-date: /usr/local/include/CADMesh/OBJReader.hh
-- Up-to-date: /usr/local/include/CADMesh/PLYReader.hh
-- Up-to-date: /usr/local/include/CADMesh/Reader.hh
-- Up-to-date: /usr/local/include/CADMesh/STLReader.hh
-- Up-to-date: /usr/local/include/CADMesh/TessellatedMesh.hh
-- Up-to-date: /usr/local/include/CADMesh/TetrahedralMesh.hh
-- Up-to-date: /usr/local/include/CADMesh/Configuration.hh
-- Up-to-date: /usr/local/lib/libcadmesh.so

I have also updated the generated cmake file so that CADMESH_INCLUDE_DIRS points to include/CADMesh so users shouldn't need to change anything after this update

[wdconinc]

Confirming that on current master this installs all headers when running make && make install instead of only CADMesh.hh without the headers it tries to include.