Minor clean-ups on sha512crypt (OpenCL) prepare.
Shrink prepare binary code.
On AMD driver 14.9 they reintroduced a bug, workaround have to be applied again.
Well, use this setup to fool the AMD driver madness.
Fix a couple of comments.
Shrink sha512 prepare further.
Use __constant if possible (sha512crypt-opencl).
Merge pull request #778 from claudioandre/bleeding-jumbo

For 14.9 driver version, AMD changed their mind again (a bug is back).