buffer: align fast buffers on 8 byte boundary
buffer: align fast buffers on 8 byte boundary

Prevents alignment issues when people create a typed array from a buffer.
Unaligned loads or stores are less efficent and (on some architectures) unsafe.

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node