Welkin Advanced Volume Overlay (for VSA)

This is a PineScript translation of Welkin's Advanced Volume Indicator Overlay, originally written for ThinkOrSwim. This tool is designed to facilitate Volume Spread Analysis (VSA) by highlighting areas of above average volume alongside price movement.

This indicator does two things:
1. Plots lines that extend from candles of above average, high, and very high volume.
2. Colors in candles with colors indicating volume levels (when "Paint Candles With Volume Colors" is enabled).

Blue lines mark candles with Average volume, based on a 20 SMA.
Orange lines mark 2-sigma (2 times standard deviations higher) volume.
Magenta lines mark 3-sigma (3 times standard deviations higher) volume.

When enabled, gray colored candles indicate below average volume.
Yellow candles indicate volume that is relatively higher than the previous candle, default is 1.25x.

Versionshinweise:

1) Added a sigma-4 level to the possible volume tiers, represented by white lines.
2) Cleaned up some plot code to make customizing colors easier.

Versionshinweise:

Added a toggle between dots and lines to make it easier to swap without having to change every plot.

Versionshinweise:

Added a visibility setting for setting transparency easily.

Versionshinweise:

Added an optional fill mode for the volume level lines to better highlight those zones.

Versionshinweise:

Added a toggle to allow for ignoring Extended Hours data when calculating volume ranges. (defaults to ON; extended hours volume is usually far below average and tends to artificially skew the results)

Versionshinweise:

Mostly cleaning up unused stuff, as well as improving some of the drawing features so you don't get angled lines from one zone to another. Also added an optional "show previous range" toggle for each sigma level.

Versionshinweise:

Fixed minor visual bug in the drawing of previous zones.

Versionshinweise:

Fixed a bug that was causing unexpected behavior for time frames between 1 hour and 1 day.

Versionshinweise:

• Added a custom timeframe option for displaying volume zones from higher timeframes.
  
• Improved visibility settings.
  

Versionshinweise:

Added line/dot thickness as a settings option.

Versionshinweise:

• Updated to PineScript 5v.
  
• Added a setting to use the "next" highest timeframe for plotting zones to make it easier to double up the indicator for multi-timeframe analysis.
  

Versionshinweise:

Forgive me father, for I have fibbed.

• Added the option to display Fibonacci levels within volume zones. Defaults to "off". This draws lines at the 0.236 and 0.618 levels between midpoint and ceiling/floor of the zones (excluding the "Above Average" zones due to plot drawing restrictions).
  

Versionshinweise:

• Cleaned up inputs and split out fills and fibs options for each individual volume level.
  

Versionshinweise:

• moar input layout tweaks.
  

Versionshinweise:

• Fixed some input layout issues.
  

Versionshinweise:

I noticed a problem with the zone drawing being off for higher timeframe (1h and greater) that I can't seem to sort out. It seems to be related to the security() calls so for now I've made a temporary fix that bypasses the security call when using the "chart" timeframe.