I just added Shamir's trick to the LTC library. Gets ~1.34x to ~1.4x
faster signature verifications than before with a simple 16 element
table of points.

Some numbers

---NOW---
ECC-112 verify_hash took 807645 cycles (1.34x faster)
ECC-128 verify_hash took 969613 cycles (1.40x faster)
ECC-160 verify_hash took 1391150 cycles
ECC-192 verify_hash...