Streaming
Added specific error message for stream variable and let-bindings
Streams
Merge commit '5624891'

Conflicts:
	Data/Array/Accelerate/CUDA/Execute.hs
Minor formatting
Loops
Formatting
Generalized ToStream and UseLazy, stream scans.
Fixed slice iteration
Added support for the Union operation.
Changes to substitution from accelerate package.
Merge branch 'master' of https://github.com/fmma/accelerate-cuda

Conflicts:
	Data/Array/Accelerate/CUDA/CodeGen.hs
Whitespace wibbles
Merge branch 'master' of https://github.com/AccelerateHS/accelerate-cuda into frederick
Bring accelerate-cuda back in line with frontend.
Remove dependency on IORefs
Merged changes from main repo.

Conflicts:
	Data/Array/Accelerate/CUDA/Array/Prim.hs
Merge branch 'master' into frederick
Match name changes in base package
Now matches the accelerate base package. Namely, we now support streamOut, streamIn and the new version of foldseq and scanseq.