* Add nlopt_get_numevals

We reuse stop.nevals which becomes stop.nevals_p, a pointer to opt.numevals, an int that we can return to the user.

* Add doc

Fix code formatting for including headers

NLopt is used as a git submodule, this allows not to confuse options of the parent project.

Install PDB file with debug information when using Visual Studio

Test shared libs on appveyor

Add namespace for CMake targets and add install include directories to target properties

Fix get|set lower|upper bounds methods warnings

Update doc

Fix all uninitialized variable warnings

Enhance testopt following #85

Use swig_add_library with cmake 3.8