Autotrader

Changes
- Improved verbosity for exception handling.
- Improved verbosity in `autotrader.py` for bot updates.
- Added utility to CCXT interface (`get_min_notional` and
`get_ticksize` methods).
- Improved CCXT `get_orders` capability.

Fixes
- CCXT interface `get_trades` method updated for `Trade` object
arguments.

Fixes
- Plotting bug when option to show cancelled orders is True.

Features
- Upgraded virtual broker: backtest speedup for large portfolio's
- Ability to specify `deploy_time` in `AutoTrader.configure()`, a datetime
object for when to release trading bots.
- Improved verbosity from main module when running.

Fixes
- Decimal error when placing market orders with `dydx` module.

Fixes
- Import error of `AutoData` in `dydx` module.

Features
- AutoBot submits orders using `ThreadPoolExecutor` to speedup
submission of multiple orders.
- Ability to provide custom execution methods via
`AutoTrader.configure(execution_method=)`.
- Improved verbosity from `autobot`s.

Fixes
- Handling of testnet/mainnet keys when paper/virtual/live trading.
- Inclusion of `__init__.py` file in `autotrader/brokers/ccxt/`.
- Timezone handling.
- Virtual broker does not use lambda functions to allow pickling.
- Unified `broker._utils` attribute naming.