Added the contact 3d + fixed two bugs in 18.04
This PR includes the contact abstraction and its 3d case (c++ code, Python bindings and its unit-test) #215 (closed). Additionally it solved a couple of compilation bugs in 18.04 #221 (closed) #186 (closed). Other tasks are:
- Removed dynamic memory allocation in ContactModel3D and partially in StateMultibody.
- Added explicit constructor in the corresponding cases.
- Written a proper guard for binding headers.
- Used
unsigned int cons&
instead ofconst unsigned int&
. - Simplified the overload methods (Python bindings) for the calc functions.