Fixed the search bar initial value and the search method

The search bar now uses placeholder instead of value to display "Search"
The search method now uses indexOf to check that the string contains the
keyword(s) instead of checking the beginning of the string.
The advanced button is now filter, search bar in under filter options
Updated the filtering options

Added difficulty filter
Changed spacing in all filter divs
Changed search function to accomodate difficulty filter
Added extra fields and variable page length
Added rotating triangles to indicate expandable fields
Added check all/check none button
Added images for difficulty
Added AJAX functions in the PHP and JS
Added basic rating selectors and fixed database creation
Made changes to the database definition and finished rating system backend
Fixed rating insertion issue
Removed debugging echos
Added login popup for non-logged in voters
Added update and return for voting
Fixed updating stars
Changed table definition
The rating and difficulty displays are now more accurate

The values are not rounded any more
There are five images for each, which are then covered relative to
rating/difficulty allow fractions of images
Removed alert for AJAX results, changed full page refresh to just
resizing the cover div for rating changes
Highlights the background of selected rating
Fixed table definition