Merge pull request #10 from TheBlueMatt/master

Fix JNI for C instead of C++
Allow private keys with less-than-32-byte secrets
Private/public key tweaking
Field 5x64
Inline asm for 5x64
1st assembly version of field 5x64 code
Merge pull request #11 from PSYCPU/master

1st assembly version of 5x64 field code
1st assembly version of field 5x64 code - bugfix
Merge pull request #12 from PSYCPU/master

5x64 assembly bugfix
Invert buggy logic in secp256k1_ecdsa_seckey_verify
Add support for multiplicative tweaking
Tweak fixes & variable name improvement
Break malleability by producing S <= order/2
updated documentation
Merge pull request #15 from haltingstate/master

updated documentation
Check for overflows when order is added at recovery
Make endomorphism optimization optional
Remove 5x64 implementation - no actual benefits
autotools: autotools'ify libsecp256k1
add missing include