AJAX in WebClient

This pull request replaces synchronous postbacks in Web Client with AJAX, improving app responsiveness.
To make grids work smoother over redraws, I've also added auto overflows to grids (so that scrollbars appear past a grid exceeding certain width) and logic to save/restore grid horizontal scrollbar position.

Had to add jQuery as a dependency to handle ajax and 'loading' modal overlays.

Also added .gitignore to make things smoother for us git users.