text: Title: Kaufman's Adaptive Moving Average (KAMA) - calculation issue
  Body: ```python
  import yfinance as yf
  from pandas_ta.overlap import kama
  import mplfinance as mpf
  
  ticker = yf.Ticker("SPY")
  minute_data = ticker.history(period="7d", interval="1m")
  
  kama_results = kama(minute_data["Close"])
  addplot = [
      mpf.make_addplot(kama_results, color='blue')
  ]
  mpf.plot(minute_data, volume=True, type='candle', addplot=addplot)
  ```
  
  ![Figure_1](https://user-images.githubusercontent.com/21048244/136270412-3e96de80-6de0-4a36-9d02-8f691ae40a72.png)
  
  I tried using the Kama indicator (snippet and picture above), seems like there's a bug with the calculate the Kama. The initial Kama value relies on the previous value which I believe from the snippet below returns zero for the first value.
  
  https://github.com/twopirllc/pandas-ta/blob/bc3b292bf1cc1d5f2aba50bb750a75209d655b37/pandas_ta/overlap/kama.py#L34
  
  [This doc](https://stockcharts.com/school/doku.php?id=chart_school:technical_indicators:kaufman_s_adaptive_moving_average) was referenced on a comment in the kama.py file and suggests that "the first KAMA is just a simple moving average".
  
  Is there anyway we can add another arg for starting_kama or generate some sma based on the "slow" length?