Updates release documentation
Updates release documentation

- Updates the PyPI release process (handled by the CI)
- Links both Travis and GitHub CI build systems
- Reformats the release checklist to blockcode for markdown

PKRoma/python-for-android,kronenpj/python-for-android,germn/python-for-android,kivy/python-for-android,PKRoma/python-for-android,rnixx/python-for-android,germn/python-for-android,rnixx/python-for-android,rnixx/python-for-android,rnixx/python-for-android,germn/python-for-android,PKRoma/python-for-android,kronenpj/python-for-android,rnixx/python-for-android,kronenpj/python-for-android,kivy/python-for-android,kronenpj/python-for-android,germn/python-for-android,kronenpj/python-for-android,PKRoma/python-for-android,kivy/python-for-android,kivy/python-for-android,kivy/python-for-android,germn/python-for-android,germn/python-for-android,PKRoma/python-for-android,rnixx/python-for-android