Various fixes and improvements.
Test tool.
Remove !>.
sha-512 hoon
sha-512 jet
Revert probably unintentional replace
add ~nosryl-tarpem as ~leb
Get at the length field of sha-512

This lets us take the hash of old-world strings with a bunch of trailing
zero bytes.
Make shal truncate ruz to len
JSON parser
Merge pull request #112 from washort/json

JSON parser
Add signed modulus
Remove unnecessary :si in si
Prevent some underflows in %fo
ed25519 toy in hoon
Check forged sigs as well
Remove magic numbers
Constant-ize constants and prime field
Inner/outer core structure, more constants
Indentation and unitization