Modified 'candlestick' function in response to request #2546

1. Added ability for the candlestick function to use a "light" and "dark" theme
2. Fill color of candlestick bodies can be user definite and is based upon stock price movement on each given period
3. In the light theme (which uses a white background) candlestick shadows are dark; ie: Follows traditional candlestick format
4. In dark theme (which uses black background) candlestick shadows match box colors