New Pull Request for #7602 and Issue #7401 .

As requested by @wilsonge to contribute these changes back to the library (https://github.com/claviska/jquery-minicolors/), i did it . The updated library includes other fixes.
A special thanks to @claviska for his suggestions, help and the time he took in make it happen!
All documentation on this color picker library available here: http://labs.abeautifulsite.net/jquery-minicolors/

Summary of Changes

• Update library jquery.minicolors.js to latest version 2.2.4 released on 18 March 2016
• Full B/C (keep previous behavior as default, both in library itself, and in Joomla)
• Add 2 form xml attributes: format and keywords
• Allow to set the format to hex (current format), rgb and rgba
• Allow usage of CSS-wide keywords transparent, initial, inherit
• Fix RTL issue with color input value (color hex and rgb(a) values should be LTR) and fix position of the picker on RTL, when using default position.

Documentation

New XML attributes

keywords (optional)

CSS-wide keywords can be assigned by setting the keywords attribute to a comma-separated list of valid keywords: transparent,inherit,initial

XML: keywords="transparent,inherit,initial"
Usage: enter the keyword in the field input (script will allow only a keyword listed in the xml attribute)
See screen shot for testing.

format (optional)

For Joomla, i've integrate the rgb(a) format option as a one xml attribute. (no need to set a data-opacity attribute).
Format could be: hex (default), rgb or rgba (with opacity slider)

XML: format="rgba"
Usage: Will return a validated color hex or rgb(a)
See screen shot for testing.

RTL support

Add RTL support. If position is default, the picker will be on the left if RTL language (currently it's right on LTR).
The input value was converted to RTL before, but with issue in some cases. To prevent this, the input value will always be LTR as it is not to be translated or converted as a CSS code value.

NOTE: When this PR will be merged, i will update JDocs accordingly ;-)

Testing Instructions

Add these fields to the settings part of an xml file of one extension (eg. template Isis). Then go to that extension settings in the admin and test the different color fields.

<field name="color1" type="color" label="Color field default (HEX)" />
<field name="color2" type="color" label="HEX + keywords" keywords="transparent,initial,inherit" />
<field name="color3" type="color" label="RGB" format="rgb" />
<field name="color4" type="color" label="RGB + keywords" format="rgb" keywords="transparent,initial,inherit" />
<field name="color5" type="color" label="RGB(A)" format="rgba" />
<field name="color6" type="color" label="RGB(A) + keywords" format="rgba" keywords="transparent,initial,inherit" />