Ref. https://github.com/humanoid-path-planner/hpp-fcl/pull/270

fix submodule url

format: clang-format-12

update deprecations for C++14

interpreter: fix deprecation for python 3.9

ref. https://docs.python.org/3/c-api/init.html#c.PyEval_InitThreads:

> Changed in version 3.7: This function is now called by Py_Initialize(),
> so you don’t have to call it yourself anymore.

> Changed in version 3.9: The function now does nothing.

> Deprecated since version 3.9, will be removed in version 3.11.

Add fwd.hh header file.

Otherwise we can't include its fwd.hh

add missing include for Boost 1.76

[CMake] set INSTALL_RPATH for python on linux

To avoid the need to set `LD_LIBRARY_PATH` when the
`CMAKE_INSTALL_PREFIX` is not a standard one.

[Python] remove references to matlab, fix #73

[CI] drop travis, fix #65

Fix build on 16.04