message: Added warning to the README w.r.t. the devel branch
diff: eos is a lightweight 3D Morphable Face Model fitting library that provides basic functionality to use face models, as well as camera and shape fitting functionality. It's written in modern C++11/14.
  +### Warning: The `devel` branch is undergoing significant changes. It currently only compiles with the latest VS2017 Preview and CMake nightly (and only fit-model and the python bindings). Please use the master branch/tag v0.12.1, unless you know what you are doing.
  +
  At the moment, it mainly provides the following functionality:
  * MorphableModel and PcaModel classes to represent 3DMMs, with basic operations like `draw_sample()`
  