Minor fixes
Merge branch 'pycuda_improvements' of https://github.com/figpope/neurokernel into pycuda_improvements

Conflicts:
	notebooks/Photoreceptor Tests.ipynb
Merge branch 'pycuda_improvements' of https://github.com/figpope/neurokernel into pycuda_improvements
Merge branch 'pycuda_improvements' of https://github.com/figpope/neurokernel into pycuda_improvements
Merge branch 'pycuda_improvements' of https://github.com/figpope/neurokernel into pycuda_improvements
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