fix #7 - Exception is raised when the Dice is flipped

[anton-ptashnik]

• fix Exception is raised when the Dice is flipped but no custom flip handler attached #7
• fix a link to PyPI package under PyPI badge
• encapsulate connection details inside a Dice constructor keeping client code unaware about an intermediate lib used for Dice communication

[anton-ptashnik]

once merged please publish the package to PyPI as v0.1.1. Below is just kindly remainder on how to publish

1. Go to Releases of the repo
2. Create a new release:
   2.1. Create a new version tag, v0.1.1
   2.2. Press Generate release notes to set a release name and default description
   2.3. Submit

Once done GitHub will publish the package to PyPI in a few seconds

[anton-ptashnik]

@Geek5510 please review