[bindings] [CMakeLists] Fix Mac and Windows library

[travis] update CI.

Guilhem Saurel authored Oct 09, 2019 and Joseph Mirabel committed Oct 23, 2019

As on some systems, we don't have OCTOMAP_INCLUDE_DIRS &
OCTOMAP_LIBRARY_DIRS but OCTOMAP_INCLUDEDIR & OCTOMAP_LIBDIR, and
therefore we get:

-- Checking for module 'octomap >= 1.6'
--   Found octomap , version 1.9.0
-- Pkg-config module octomap v1.9.0 has been detected with success.
-- FCL does not use Octomap

[bindings] [CMakeLists] Use .so for Mac and .pyd for Windows, fix #86

Organize documentation

delete one class, 2 class are the same

add inline to initialize

[Minor] update CMake module + fix visibility of some methods.