1. stretch the mouse input js out. 2. make the toy_data generator
modular 3. redesigned the left side panel, make it modular. 4. make the
content aligned center. 5. make an option for whether the coordinate
system has a background heatmap. 6. add the README
Merge pull request #8 from foulwall/refractor

new toy_data generator, style, readme. and did some code refractor