swc.css: Add striped rows to tables
swc.css: Add striped rows to tables

Now the style is matching closely `.table-bordered` from Bootstrap.
I decided to leave the header row background blank because it was too
close in color to `#F9F9F9` - our new rule for even rows in the table.

I also increased horizontal padding by 5px on both sides, because now
that we have vertical borders it was too cramped.

Additionaly I introduced borders for every cell in the table.

easyreporting/fmri_reporting,dleehr/organization-RR-Jupyter,Reproducible-Science-Curriculum/rr-automation,dleehr/organization-RR-Jupyter,Reproducible-Science-Curriculum/rr-automation,butterflyology/rr-intro,Reproducible-Science-Curriculum/rr-literate-programming,butterflyology/rr-intro,butterflyology/rr-intro,butterflyology/rr-intro,Reproducible-Science-Curriculum/rr-literate-programming,butterflyology/rr-intro,easyreporting/fmri_reporting,RobIsaTeam/courses,easyreporting/fmri_reporting,dleehr/organization-RR-Jupyter,dleehr/organization-RR-Jupyter,butterflyology/rr-intro,RobIsaTeam/courses,easyreporting/fmri_reporting,dleehr/organization-RR-Jupyter,dleehr/organization-RR-Jupyter,easyreporting/fmri_reporting,easyreporting/fmri_reporting