🚀 Release v0.5.2 (executablebooks#47)

🚀 RELEASE: v0.5.1

🚀 RELEASE: v0.5.0

bump version

Add `badge` and `link-badge` roles (executablebooks#27)

Override `.btn:visited` CSS (executablebooks#13)

This is set if using the parent RTD theme and was overriding any colors set by the bootstrap classes

Add `link-button` directive (executablebooks#12)

Create clickable buttons, referencing URLs or References

Improve option syntax (executablebooks#10)

The panel level options now use the same format as normal options, e.g. card `+= shadow` to `:card: + shadow`, whereby a `+` at the start indicates additive behaviour.

Also, the delimiters are now configured as regexes, for greater flexibility, and the default panel delimiter has been changed back from `...` to `---`.

Merge pull request executablebooks#3 from executablebooks/testing2

update docs