Add NaN checker control for fp buffers and images

[Novermars]

Add a control which checks all fp buffers/images for NaNs, outputs the first kernel which causes such a NaN to appear. Possibly before and after a kernel enqueue, to prevent garbage in == garbage out.

For debugging, it can be nice to detect the first time a NaN appears, so that this kernel and its inputs can be captured and replayed for further analysis.

Probably needs kernel argument reflection, to prevent false positives in int buffers or OpenCL images for which have an integer as underlying data type.

Give me a few days and I'll prepare a merge request :)