Fix 1.1.0 release (#43)

These changes:

 - bump package version to 1.1.0

 - strip the version string in setup.py in order to avoid a packaging issue
   https://travis-ci.org/opentracing-contrib/python-flask/jobs/600396363#L315
   pypa/setuptools#1390

 - declare support for Python 3.8
   https://discuss.python.org/t/python-3-8-0-is-now-available/2478

 - update .travis.yml

 - add long_description_content_type to setup.py

Update VERSION

Update VERSION

Add default to _after_request_fn (#6)

Merge pull request #11 from opentracing-contrib/py3

disabled upper limit on opentracing python lib

v0.1.8

Update VERSION

Update VERSION

Update VERSION

Update VERSION