Add PPO (Percentage Price Oscillator)

Joel Nolasco commented
The PPO is similar to the MACD, except it uses a more complex but more reliable percentage formula. At first glance on a graph the MACD & PPO looks the same. The primary difference in these indicators, the MACD is based on the difference between the 12 day EMA and the 26 day EMA expressed in DOLLARS, while the PPO expresses this difference in PERCENTAGES. Its impossible to compare the relative momentum of two stocks with varying prices using MACD. Why ? Because higher dollar stocks will have higher dollar differences between its 12 day EMA and 26 day EMA. The PPO however is perfect to make that comparison because it's based on percentage instead.

Joel Nolasco commented
The Percentage Price Oscillator is similar to the MACD, except the PPO uses a more complex, but more reliable formula. It is based on the percentage difference between two moving averages over a given period of time. It uses two lines, one thick and one thinner, to display its information.