Add session-data recording, server to store data
This commit adds basic functionality for recording session data. It adds
methods to the original Tetris code to record the data, and sends the data to a
server via a POST request. It also creates a simple PHP server to receive and
store this data.
Add framework for parsing exported JSON data
The commit creates a second set of files to be used for parsing exported
session data. Currently this is just a framework without any functionality.

Parsers will be added as separate HTML files, embedded as frames in the
parsing.html page. They can access the game data through sessionStorage.