fix/add missing 'LIBUSB_CALL' at libusb callback 'hackrf_libusb_transfer_callback'

Merge pull request #382 from dominicgs/operaglasses

Always call hackrf_set_hw_sync_mode in hackrf_transfer.

Added "Waiting for sync" info in hackrf_transfer

Avoid hackrf-transfer to abort if no samples are received within one second, when hardware sync mode is enabled.

Opera glasses: allow user specified ranges for operacake ports

cleanup

Hardware (CPLD-based) synchronisation

Removed decimation in CPLD

Fixed indentation