This is mostly implemented for `clGetKernelArgInfo` [1] called with
`CL_KERNEL_ARG_TYPE_QUALIFIER`. Since an argument can have multiple
type qualifiers (e.g. `const` and `volatile`), this returns the bitwise
or of the flags that we need to separate.

[1] https://www.khronos.org/registry/OpenCL/sdk/1.2/docs/man/xhtml/clGetKernelArgInfo.html

Add missing handling of cl.kernel_arg_info.TYPE_QUALIFIER

See merge request !99

Mention oclgrind, intel-compute-runtime and beignet

See merge request !97

Use numpy 1.17.3 for python 3.8

Remove hashlib fallback for Py <2.5

See merge request !98

Rebuild from source if cached version causes BUILD_PROGRAM_FAILURE

Update docs for how to install system ICDs in Conda Forge

See merge request !96

Switch from array.vec to cltypes in image_from_array

See merge request !95

Implement get_async

Closes #18

See merge request !91

docs(README.rst): embrace https links

Changed links that were in http protocol and confirmed supporting https to https.

Changed links that were in http protocol and confirmed supporting https to https.

Do not release gil in nanny event destructor

See merge request inducer/pyopencl!92