modularize src

+ merge main.py and manage.py
+ move start logic to swingmusic/__main__.py
+ add a run.py on the project root

swingmusic/lib/pydub/.travis.yml

@@ -0,0 +1,19 @@
+os: linux
+dist: bionic  # focal
+language: python
+before_install:
+  - sudo apt-get update --fix-missing
+install:
+  - sudo apt-get install -y ffmpeg libopus-dev python-scipy python3-scipy
+python:
+  - "2.7"
+  - "3.6"
+  - "3.7"
+  - "3.8"
+  - "3.9"
+  - "pypy2"
+  - "pypy3"
+script:
+  - python test/test.py
+after_script:
+  - pip install pylama && python -m pylama -i W,E501 pydub/ || true