Add:
templates/index.html
-Add compartmental `div` structure for the advanced-search form.
static/sass/index.sass
-Add layout style rules to the advanced-search form.
app.py, templates/(about, developers).html
-Add `Flask` routes and skeleton files for pages to be developed later.
Ref:
static/js/index.js
-Substitute some verbose `JavaScript` calls with their `jQuery`
equivalents.