495 clear button

Fixes #495 
- Adds search input manager for handling input clear button—little (x).
- Disables autocomplete because field highlight color can’t be
overridden.
- Removes unused data-list attributes.
- Adds tests for clearing the input fields.

Also: 
- Normalizes button and form id/class names using the specificity
principle (general --> specific).
- Removes unused classes from submit/reset buttons.