Define packages to install

[dominikgrygiel]

This change should help with installation, ex. in conda environments. Before the change only .dist-info would be installed without actual code, which would lead to ModuleNotFoundError.

Before:

> pip install -vvv https://github.com/Kismuz/btgym/archive/master.zip 2>&1 | grep adding
  adding license file "LICENSE" (matched pattern "LICEN[CS]E*")
  creating '/tmp/pip-wheel-tg6zdmzr/btgym-0.0.8-cp36-none-any.whl' and adding 'build/bdist.linux-x86_64/wheel' to it
  adding 'btgym-0.0.8.dist-info/LICENSE'
  adding 'btgym-0.0.8.dist-info/METADATA'
  adding 'btgym-0.0.8.dist-info/WHEEL'
  adding 'btgym-0.0.8.dist-info/top_level.txt'
  adding 'btgym-0.0.8.dist-info/RECORD'

After:

> pip install -vvv https://github.com/dominikgrygiel/btgym/archive/master.zip 2>&1 | grep adding
  adding license file "LICENSE" (matched pattern "LICEN[CS]E*")
  creating '/tmp/pip-wheel-8bb3f3z9/btgym-0.0.8-cp36-none-any.whl' and adding 'build/bdist.linux-x86_64/wheel' to it
  adding 'btgym/__init__.py'
  adding 'btgym/dataserver.py'
  adding 'btgym/server.py'
  adding 'btgym/spaces.py'
  adding 'btgym/algorithms/__init__.py'
  adding 'btgym/algorithms/aac.py'
  adding 'btgym/algorithms/envs.py'
  adding 'btgym/algorithms/math_utils.py'
  adding 'btgym/algorithms/memory.py'
  adding 'btgym/algorithms/rollout.py'
  adding 'btgym/algorithms/test.py'
  adding 'btgym/algorithms/utils.py'
  adding 'btgym/algorithms/worker.py'
  adding 'btgym/algorithms/launcher/__init__.py'
  adding 'btgym/algorithms/launcher/base.py'
  adding 'btgym/algorithms/launcher/meta.py'
  adding 'btgym/algorithms/nn/__init__.py'
  adding 'btgym/algorithms/nn/ae.py'
  adding 'btgym/algorithms/nn/layers.py'
  adding 'btgym/algorithms/nn/losses.py'
  adding 'btgym/algorithms/nn/networks.py'
  adding 'btgym/algorithms/policy/__init__.py'
  adding 'btgym/algorithms/policy/base.py'
  adding 'btgym/algorithms/policy/meta.py'
  adding 'btgym/algorithms/policy/stacked_lstm.py'
  adding 'btgym/algorithms/runner/__init__.py'
  adding 'btgym/algorithms/runner/base.py'
  adding 'btgym/algorithms/runner/synchro.py'
  adding 'btgym/algorithms/runner/threadrunner.py'
  adding 'btgym/datafeed/__init__.py'
  adding 'btgym/datafeed/base.py'
  adding 'btgym/datafeed/casual.py'
  adding 'btgym/datafeed/derivative.py'
  adding 'btgym/datafeed/multi.py'
  adding 'btgym/datafeed/stateful.py'
  adding 'btgym/datafeed/test_casual_data.py'
  adding 'btgym/datafeed/test_data.py'
  adding 'btgym/envs/__init__.py'
  adding 'btgym/envs/base.py'
  adding 'btgym/envs/multidiscrete.py'
  adding 'btgym/envs/portfolio.py'
  adding 'btgym/monitor/__init__.py'
  adding 'btgym/monitor/tensorboard.py'
  adding 'btgym/monitor/tensorboard2.py'
  adding 'btgym/rendering/__init__.py'
  adding 'btgym/rendering/plotter.py'
  adding 'btgym/rendering/renderer.py'
  adding 'btgym/strategy/__init__.py'
  adding 'btgym/strategy/base.py'
  adding 'btgym/strategy/observers.py'
  adding 'btgym/strategy/utils.py'
  adding 'btgym-0.0.8.dist-info/LICENSE'
  adding 'btgym-0.0.8.dist-info/METADATA'
  adding 'btgym-0.0.8.dist-info/WHEEL'
  adding 'btgym-0.0.8.dist-info/top_level.txt'
  adding 'btgym-0.0.8.dist-info/RECORD'

[Kismuz]

@dominikgrygiel, LGTM, thanks for contribution!