main.cpp gets shorter, CMakeLists.txt gets longer, door opens for
conditional compilation of plugins.

main.cpp gets shorter, CMakeLists.txt gets longer, door opens for
conditional compilation of plugins.

- rename eosd to eosiod
- rename eosc to eosioc
- rename eos-walletd to eosio-walletd
- fix wallet plugin
- fix producer plugin
- eosiod will now produce blocks every 500ms
- rename eos_chain to eosio_chain
- move include/eos to include/eosio for various libraries

- support fetching tables
- update readme to show fetching tables
- support multiple scopes with -S
- changed docs to use long args rather than short
- implement wast_to_wasm and wasm_to_wast
- support fetching code and abi from blockchain with eosc
- update definition of abi for currency contact
- add extra meta info to Abi type to describe tables

- added account fetching in CLI
- added currency.abi file describing currency contract's ABI

1. remove ordered_non_unique non-deterministic indices from producer
scheduling
2. added API to return contents of i64 tables
3. updated documentation to reflect deprecation of precondition and
validate
4. remove calls to WASM precondition and validate, but keep them for
native contracts

In original design all messages passed between contracts would consist
of well defined types, these types would be used with code generation to
parse message data and then pass rich Wren objects to user defined
message handlers.  The switch to Web Assembly made this irrelevent and
counter productive.

Going forward applications will be able to define and publish their own
ABI and serialization techniques. This will make the core platform simpler.

Fixed code caching

- Break apart chain_controller, so it doesn't inherit
chainbase::database
- Reorganize chain_controller, database (and whatever else) towards
dependency injection
- Reorganize chain_controller, database (and whatever else) towards RAII

Rename database class to chain_controller, as this class manages
blockchain state and operations. Database was a misnomer.

Next step: make chain_controller a free-standing class, rather than
having it inherit from chainbase::database. This should give us a better
architecture, especially for testing, going forward.

Create a new read-write chain API with push_block and push_transaction
calls

Add get_block call to chain read_only api

The beginnings of the chain API is now much closer to the design
described in #14

Only one call, but that call works!