Check forged sigs as well
Remove magic numbers
Constant-ize constants and prime field
Inner/outer core structure, more constants
Indentation and unitization
Make ed toy more interesting
Add disclaimer
Extract cryo
Comments, s/decp/deco/
Revert "Add signed modulus"

This reverts commits 5fa624d27e4e6ae3b9d268b02ce79b712598caff and
81cc1d5632415f2b4e661f754b324a9b66875198.
Splinter out ed toys