Grant Wuerker

WASI imports

1

Addresses #178 Added a new import list identified by "wasi", which contains all of the the functions listed in the [latest API snapshot](https://github.com/WebAssembly/WASI/blob/master/phases/snapshot/docs.md#functions).

EIP152 blake2F

3

Closes #36 This PR adds support for [EIP152](https://eips.ethereum.org/EIPS/eip-152). Each test case described in the document is passing and benchmarking on my personal laptop suggests this is fast enough. The 1200...

Includes useful macros for creating ASTs and some additional structs.