Vector Extension 1.0, frozen for public review

This version 1.0 is considered frozen for public review as part of the RISC-V International ratification process. Version 1.0 is considered stable enough to begin developing toolchains, functional simulators, and implementations, including in upstream software projects, and is not expected to have incompatible changes except if serious issues are discovered during ratification. Once ratified, the spec will be given version 2.0.