frame.create fails if stylesheet or html specified does not exist
Roadmap updates for 0.3
Changelog updates for 0.3
QElement.assert()
Example is updated for v0.3
API documentation updates for 0.3
Readme tweaks
INTEGRATE: 0.3 documentation and QElement.assert()

* dev:
  Readme tweaks
  API documentation updates for 0.3
  Example is updated for v0.3
  QElement.assert()
  Changelog updates for 0.3
  Roadmap updates for 0.3
Merge branch 'createFrameWithMissingFile' of https://github.com/bjornicus/quixote into dev
Code style tweaks
Contribution credit for @bjornicus
Frame.create() enhancement in changelog
INTEGRATE: Frame.create() fails fast when URL not found

* dev:
  Frame.create() enhancement in changelog
  Contribution credit for @bjornicus
  Code style tweaks
  frame.create fails if stylesheet or html specified does not exist
0.3.0