making html consistent and getting javascript ready

Adding schedule.html and sessions.html and javascript shell and making
the html files consistent with same header, footer and nav
Styling schedule page

added schedule.scss and some minor mods to related field and html to
match
Styling the Home Page

Added in some different layouts at different breakpoints.
Styling the About Page

Also made some changes to how colors are handled by making a separate
file for color variables.
moving color vars to separate file
Adding and Styling Sessions page

This was based on the work we did in class on 12.8 with a student
project.