Graph-plotter

Plot any function of $x$ on a $xy$ plane, zoom in/out and check the coordinates.
To use common math functions like $sin(x)$, add Math. in front of the function e.g. Math.sin(x)

TODO:

• plot multiple plots on the same graph
• zoom in/out using mouse scroll wheel
• pan the graph
• checkEquation should have a better parser for Math.<functions>. Math. should not have to be added
• handle asymptotes as moveTo() joins the plot in that case. Same with non-continous functions