Bug 979

CLBufferTest's test of createSubBuffer fails on AMD devices
correctly due to not considering CL_DEVICE_MEM_BASE_ADDR_ALIGN.

"CL_MISALIGNED_SUB_BUFFER_OFFSET is
returned in errcode_ret if there are no devices in
context associated with buffer for which the origin
value is aligned to the
CL_DEVICE_MEM_BASE_ADDR_ALIGN value."

Each device has it's CL_DEVICE_MEM_BASE_ADDR_ALIGN attribute
and buffers used for a specific device must be aligned to it.

In case the OpenCL implementation does not fail w/ above
operation, subsequent buffer operations (enqueue .. etc) may fail later.

+++
typedef unsigned __int32        cl_uint;

cl_uint CL_DEVICE_MEM_BASE_ADDR_ALIGN:

"The minimum value is the size (in bits) of the largest OpenCL built-in
data type supported by the device (long16 in FULL profile, 
long16 or int16 in EMBEDDED profile) for devices that are not of type
CL_DEVICE_TYPE_CUSTOM ."

+++

I experimented w/ reading our said value and aligned the sub-buffer
offset as specified, which works well.

However a major problem is that the offset and size values passed 
to CLBuffer.createSubBuffer(..) do not reflect the byte-size,
but the element-count.

Implementation must correct the byte-offset to be aligned properly.

Further more, another complication is the lack of knowledge 
for which device the buffer shall be aligned to.
Hence a device attribute may be given here as a hint.
If the latter does not to exist, we would need to align the buffer for all devices.

+++

I currently re-implement a general purpose bitstream reader
allowing properly fetching values like cl_uint .. etc.

+++