{% checkbox style parameter (optional), text (support simple md) %}

{% checkbox plain text test %}
{% checkbox checked, supports simple [markdown](https://guides.github.com/features/mastering-markdown/) syntax %}
{% checkbox red, support custom color %}
{% checkbox green checked, green + default selected %}
{% checkbox yellow checked, yellow + default selected %}
{% checkbox cyan checked, cyan + default selected %}
{% checkbox blue checked, blue + default selected %}
{% checkbox plus green checked, increase %}
{% checkbox minus yellow checked, reduce %}
{% checkbox times red checked, cross %}