This is done to comply with the policy that transactions should be self
describing and not depend upon implied state. This makes things easier
for everyone to understand exactly when a transaction will be invalid
without having to refer to chain state.
- remove circular dependency with fee_schedule
- unitiy build db_* as database.cpp
- move protocol definitions in separate directory
- combined some objects/evaluators
- combined limit/call evaluator/objects into market_evaluator.*
Core exchange rate is now redundantly stored in price feed for
bitassets, and updated when the median feed changes. This allows feed
producers to update the core exchange rate. Redundant storage is
necessary, because the core exchange rate is needed for user-issued
assets as well as market issued assets.