Pivot Points & Midlines with color selector

Adapted from Pinescript Manual's "Pivot Points Standard". Added extra levels and midlines as well as user inputs for color and a "show labels" on/off switch.
So this will show the Pivot level, the resulting levels R1,R2,R3,S1,S2,S3 and the midpoint lines between these.
User can choose the Higher timeframe period from which to calculate these pivot levels, as per the original script.
I like to add two of these to a chart, one for daily and one for weekly pivot levels.
If you don't need any particular level, just comment out the appropriate lines (one from each of the second last and third last blocks in the script).

Notes de version:

~added Previous day's high and Previous day's low
~limited the number of historical levels as much as possible (you can tweak these by editing up the numbers in line 8; unfortunately, if you try to make them lower than 26, it throws an error)

Notes de version:

~allow to show Previous day's highs & lows ONLY
~allow to show Pivot& midlines lines ONLY
(default is show all)

Notes de version:

-show/hide previous day levels; added user option toggle on/off. Default is not show.

Notes de version:

-Added option to print price labels
-Cleaned up code

Notes de version:

-added label position choice (left or right).
-added offset bars for current day's labels (offset +(right) or -(left) of last bar index. Only applies when label position is set to 'right'.