Add support for OpenCL 1.0 devices

[bmerry]

Currently the startup code checks that the device supports OpenCL 1.1. It should be sufficient if the platform supports OpenCL 1.1, even if the device is only OpenCL 1.0 compliant - as long as it has the right capabilities.

Originally this couldn't be done because clogs could not handle G80 NVIDIA devices, but clogs 1.2 should work with such older devices.