Implemented a Round 3 tweak described in the Ascon v1.2 specification, Appendix B, Section B.2.

Extended and formatted according to the recommendations entitled: Verilog/VHDL Code: Suggested List of Deliverables v1.0

Removed support for the Length Segment, as recommended in the Addendum to the CAESAR Hardware API v1.0.
Added support for the generic G_MAX_LEN, and thus two possible maximum lengths of AD/message/ciphertext, equal to SINGLE_PASS_MAX (representing 2^32-1) and TWO_PASS_MAX (representing 2^11-1), as recommended in the Addendum to the CAESAR Hardware API v1.0.