No OpenCL initialization whatsoever until opencl_init_opt().
Call OpenCL related functions only at format init(). - also, use make sequential_id an int.
Remove unnecessary OpenCL init() functions.
Merge branch 'bleeding-jumbo' into memdbg

* bleeding-jumbo:
  Remove unnecessary OpenCL init() functions.
  Call OpenCL related functions only at format init(). - also, use make sequential_id an int.
  No OpenCL initialization whatsoever until opencl_init_opt().

Conflicts:
	src/common-opencl.c