Relocate importable files into their own folder

[kfsone]

Since 3.something Python often gets irritable when you have top-level and import scripts in the same path. This causes some weirdness when developing because trade.py has this:

from tradedangerous import cli

but trade.py is inside the tradedangerous folder; so there's the potential that a shenanigan'd virtual or conda env might import from a different tradedangerous folder than the local one...

Common solutions are:

• have a subdirectory for "executables" (often 'cmds', 'cli' or 'bin') - never done this, but when you've pip installed something that puts stuff in your path its often this approach,
• have the front commands in the directory above the package:

  ./Trade-Dangerous/
  | trade.py
  | tradedangerous/
  | | tradedb.py

• a subdir:

  ./Trade-Dangerous/
  | tradedangerous/
  | | trade.py
  | | tradedangerous/
  | | | tradedb.py

[eyeonus]

Option 2. We'll have to move both trade.py and tradegui.py, and fix the entry points in setup.py:

        entry_points = {
            "console_scripts": [
                "trade=tradedangerous.trade:main",
                "tradegui=tradedangerous.tradegui:main"
            ]
        },