Increased max USB transfer size and modified XSCOPE for the control application

[lucianomartin]

• updated USB control transfer size to 2048 bytes
• moved definition of USB_TRANSACTION_MAX_BYTES to header file, as it is done for the other transport protocols
• removed pause in XSCOPE control since it was delaying the tuning tests. Removing the pause didn't cause any instability
• added and used XSCOPE_DATA_MAX_BYTES

[xross]

This is blocking XVF release. Needs releasing.

[xross]

Needs a change log update and a version bump

[larry-xmos]

Could you please update copyright notices in files that have changed? Just need changing "(c) 2016" to "(c) 2016-2017" in:

• examples/xscope/host/src/pause.h
• lib_device_control/host/device_access_usb.c
• lib_device_control/host/device_access_xscope.c
• lib_device_control/host/util.c