LowerBollinger band for any indicator
Syntax	Lbband[definedindicator;noofdays;standarddeviation;daysebfore]
Description	To find out lower band of bollinger band using noofdays and provided standard deviation for any defined indicator use this formula.
Example	Suppose you need to get value of lower band of bollinger for 20 days using 2 standard deviation for lower value the formula will be Lbbandany[low[0];20;2]