place a vwap line starting from the line placed on the chart
parameters:
tick_mode: enable to use ticks instead of bars. this uses a lot more cpu processing power
prefix: prefix to add for line created by indicator
line_color: set the color of the line created
line_style: set the line style of the line created
applied_price: set the price of bar to use of the bar
std_dev_ratio: set the multiplier for the std dev channel
