List of toolkits for algorithm visualization

Each of these comes with a set of demos
Merge pull request #1 from redblobgames/master

List of toolkits for algorithm visualization
added newton-raphson links
Merge pull request #2 from dannyko/master

added newton-raphson links
Merge pull request #1 from enjalot/master

Merge master
Added more examples

For "Projects" added sites that have sets of math/algo visualizations; for "Examples" added individual pages; "References" are about visualization.
Fix typo
Merge pull request #3 from redblobgames/master

Added lots more links
Added a few more links.