Generate and install CMake config

[wxmerkt]

Following jrl-umi3218/jrl-cmakemodules#247, can we please add the necessary features to generate and install the cmake config such that the only requirements to use eigenpy reduce to:

find_package(eigenpy REQUIRED)

And can we please tag a release using the latest two PRs and this CMake configuration.

(I tried it following the comment in jrl-umi3218/jrl-cmakemodules#247, but didn't get it to install yet)

[jcarpent]

Solved by #132.