Add chart component

[protibimbok]

No description provided.

[permafrost06]

Stuff that needs to change:

• The points in linechart should be connected by straight lines, instead of polynomial curves.
• For the component demos, instead of generating random values when something changes, create inputs for every data point. Create a button for radom generation.
• Add support for labels.

[permafrost06]

Looks good. Now, we'll need a good default style.

[protibimbok]

Design References:

[permafrost06]

Add a full-circle variant for the pie (arc) chart.
Add legends to both charts.
Add a stacked bar chart