Moderngl-window

* Fixed several issue related to python 3.5 support
* Upgraded to pywavefront 1.2.x
* Renamed some modules and classes to better reflect their capabiltities
* Renamed some inconsistent parameter names in the codebase
* Complete overhaul of docstrings in the entire codebase
* Added missing type hints
* Revived the STL loader
* Documentation
* Added `moderngl_window.__version__` attribute

* GL errors during window creation is now consumed. This is to avoid confusion when this state is set in the rendering loop.
* Default anisotropy for textures loaders is now 1.0 (disabled, isotropy)
* Mipmaps are no longer generated by default. You must explicitly enable this in parameters.
* WindowConfig.load_texture_2d now exposes more parameters
* WindowConfig.load_texture_array now exposes more parameters
* WindowConfig.load_scene now exposes more parameters
* Texture loaders supports specifying mipmap levels
* Texture loaders supports specifying anisotropy
* VAO wrapper supports normalized float/uint/int
* More tests

* Supported buffer formats in the VAO wrapper now matches moderngl better
* VAO wrapper now uses buffer format strings matching moderngl including divisors
* Fixed some logging issues

Initial release