Heikin Ashi RSI Oscillator

Introducing HARSI - the RSI based Heikin Ashi candle oscillator.

...that's right, you read it correctly. This is Heikin Ashi candles in an oscillator
format derived from RSI calculations, aimed at smoothing out some of the
inherent noise seen with standard RSI indicators.

Science!

We likes it we does.

Included plot options for standard RSI plot overlay, and a smoothed variant with
it's own seperate length from the candles, oh and histogram option, for reasons.

Articles and further reading:

• investopedia.com - RSI
  
• investopedia.com - Heikin Ashi
  

This is a REALTIME indicator, so any values used for conditions should use
history 1, or alternatively, alerts should be called using once-per-bar-close.

Versionshinweise:

Removed:

• Rogue f_getRGBA() function that slipped through the pre-publication pass. This has zero impact on anything.
  
• Candle border colour selection - it is now tied to candle body colour to preserve colour clarity at smaller scales.
  

Changes and Adjustments:

• plotcandle() title is now simply "HARSI", this makes it easier to select O/H/L/C options in the alerts tab. They now display as "HARSI Open", "HARSI High", rather than "HARSI Candle ..".
  
• Reduced the default RSI plot length to 7, while keeping the default of 14 for the candles.
  
• RSI plot and Histogram are both now enabled by default, with smoothing option active.
  

Additions:

• Added additional "extreme" Overbought and Oversold h-lines, these default to +30, and -30.
  
• Added option to apply smoothing to the Open of the HARSI candles, this is simply an extension to the base Heikin Ashi Open calculation to help better visualise trend strength if desired. This setting defaults to 1 (no smoothing) see below for comparative image.
  
• Added descriptive tooltips for the candle config section.
  

smoothing comparison:

Versionshinweise:

Improved candle open smoothing feature.

Versionshinweise:

Apologies for double update!

• Forgot to update tooltip to better describe the updated smoothing algo for candle open - fixed.
  
• Fixed minor typo in the background fill section.
  

Versionshinweise:

• Added Stochastic RSI as an option, which utilises the setting defined in the RSI config section. This can be displayed in standard dual-plot mode, or ribbon fill.
  
• New function `f_zstoch()` generates Stochastic RSI with zero median, and percentage scaling. The scaling should not affect crossing signals.
  
• Updated and consolidated input tooltips to their own section.
  
• Consolidated color variables to the proper location.