* use UK spelling of colour

* Increment version number to 0.4.2.9000

* docs: add NEWS item

* chore: devtools::document()

---------

Co-authored-by: Garrick Aden-Buie <garrick@adenbuie.com>

Co-authored-by: gadenbuie <gadenbuie@users.noreply.github.com>

* Increment version number

* Better horizontal alignment of code blocks

* Use testthat 3e

* Use expect_known_output() because we need the css files

* Replace `with_mock()` with `mockery::stub()`

* Remove extraneous line

* Set ml and mr for all horiz alignment classes

* Add NEWS for #68

- Move long intro to pkgdown
- README is now much shorter
- Rename pkgdown "Get Started" to "Features"
- Add ggplot theme to quick intro
- Add pkgdown docs link to description

And add tests

Now, font size is inherited from `base_font_size` which should be in absolute units.

Inspired by tachyons, easily add additional colors to slides using the `colors` argument. The argument takes a named list or vector and adds a CSS variable with the color name. Also added are .<color> and .bg-<name> classes.

Also allow NULL or NA for template arguments but change default to NULL

- Update license, description
- Add documentation, images and gifs

- write_xaringan_theme works
- mono_* works