Fix test

YouTube embeddings have a minimum height of 200
Remove codeq.io badge

Seems to be defunct
Include license in README
Initial cut of formatting with template
Include content_url in template parameters
Extract default embeddings as templates
Documentation
Add test for case when template is not found
Merge pull request #27 from matt-thomson/issue5

More control over embedding format
Use new PyPI deployment
Merge pull request #29 from matt-thomson/v0.4.0-dev

V0.4.0 dev