update types and constants for OpenCL 2.0
adds opencl 2.0 api
small fixups
Merge pull request #60 from JuliaGPU/vc/opencl20

API support for OpenCL 2.0 fixes #56
simplifies the test logic and removes cruft
adds colour output for tests
move create_test_buffer
use let clause instead of global const
fixes typo that ended up creating a global reference
use onlystats
Merge pull request #61 from JuliaGPU/rework_test

[RFC] Rework test
use Compat to remove syntax deprecations