Data queue FIFO included in uLUt.

Data queue FIFO included in uLUt.

The FIFO support functions and type for custom element
can be declared by UL_DQFIFO_CUST_DEC. The static
instances can be declared by UL_DQFIFO_STATIC_INSTANCE.
The FIFO size has to be power of two, because sequential
numbers are masked when index into buffer is computed.

Queue allows to iterate over last N elements in addition
to usual put and get operations which is significant
for FIR filters implementation.