Update README.md
Merge pull request #108

6c7f0c6 Update README.md (Pieter Wuille)
Add DETERMINISTIC to avoid line number/source dependent binaries

This will make it easier to detect changes without semantic impact.
Merge pull request #107

f49b2ef Add DETERMINISTIC to avoid line number/source dependent binaries (Pieter Wuille)
Make secp256k1_eckey_pubkey_serialize fail for infinity
Test whether recovered public keys are not infinity

Fixes a bug discovered by Sergio Demian Lerner.
Add test that recovering infinity fails
Merge pull request #110

3bf029d Add test that recovering infinity fails (Pieter Wuille)
4861f83 Test whether recovered public keys are not infinity (Pieter Wuille)
bbe67d8 Make secp256k1_eckey_pubkey_serialize fail for infinity (Pieter Wuille)
Use Co-Z arithmetic for precomputations

- Selected Co-Z formulas from "Scalar Multiplication on Weierstraß Elliptic Curves from Co-Z Arithmetic" (Goundar, Joye, et. al.) added as group methods with new type sep256k1_coz_t.
- Co-Z methods used for A and G point precomputations.
- WINDOW_A size increased to 6 since the precomputation is much faster per-point.
- DBLU cost: 3M+4S, ZADDU cost: 5M+2S.
- Take advantage of z-ratios from Co-Z to speed up table inversion.