Prune exchange-libs
deploy migrations at specific address
remove exchange-libs, moving LibMath into Utils
Remove staking order-utils multisig and remaining asset-proxy
* generate wrappers in @0x/contract-wrappers and delete abi-gen-wrappers
* trim exports from contract-wrappers
* separate contract-wrappers tests to get rid of dependency cycle
* remove dummy token contracts
* temporarily skip coordinator test until we can upgrade coordinator server
