Update Charting/Example to be SMA Cross

[jaredbroad]

Using a more classical indicator plot would be more helpful to most people. https://www.quantconnect.com/docs/v2/writing-algorithms/charting#08-Examples

Expected Behavior

Show SMA200 / SMA 50 plot as example not SPY asset pricing.

[AlexCatarino]

Closed by c0809e9. Using two EMA 20 and 50 to cross and plot triangles using the price when they cross.