Also:
* Disallow executing a proposed transaction if it has expired.
* Correct bug with return value of check_authorization (provided_delay
should not be considered in max_delay).
* Check expiration, TaPoS, and valid referenced accounts prior to other
transaction_context initializations (primarily to get more meaningful
error messages).

Changed fixed size type T v[N] to use format similar to std::vector, so that abi serializer can serialize both types the same way. GH #2350

unify template specializations for fundamental types, exclude fundamental types from the specialization that uses boost::pfr::for_each which appears unsafe in this use case for fundamental types EOSIO/eos#2069

implment stub of new eosio.msig contract using new contract structure
define eosio.msig abi
eoslib name class now uses {} rather than constructor and uses magic_get
serialization

- attempt at implementing new dispatcher

Implemented Test:
   - issue two currencies USD and BTC via @currency contract
   - create EXC exchange between USD and BTC
   - buy BTC with USD and then sell proceeds back for BTC
   - verify only error is rounding error in favor of exchange

Added missing Float compilier intrensics
Added flaot64 types to WAVM api
Added print functions for asset in WASM contracts

rename eos_assert to eosio_assert, implement is_account() api, and move implementation from apply_context.hpp to .cpp