Update to OpenCL 3.0

[lilkeet]

This pr updates the wrapper to support OpenCl up to version 3.0.
In the process, it also solves issue #8.

Other notable changes:

• A fair amount of mangling is done so that all types and procs are more Nim-like than C-like.
• The naming conventions follow the nep1 style guide.
• Documentation comments are added.
• The vector types are now included, solving issue Vector types #8. A dependency on nimsimd is used for some of the SIMD types.
• The compatibility module for mixing OpenCl with OpenGl is included.
• Simple test examples for all versions after 1.2 are added.
• Enums are actual enums instead of consts.
• Bitflag enums are actually sets, so the incl and excl procs are used instead of or.