EIP-615: Subroutines and Static Jumps for the EVM

[veox]

The links in above copy-paste (in order of appearance):

• Immutables, invariants, and upgradability
• EVM instruction set versioning
• https://github.com/ethereum/EIPs/pull/1712
• https://github.com/sorpaas/EIPs/issues/4
• https://github.com/ethereum/EIPs/issues/154
• https://github.com/ethereum/EIPs/pull/1707