* added standardize greys
* replaced '$subtle-gray' references with '$gray-05'
* updated double-quote-glyph.svg so it's in '$gray-05' colour
* updated cta-card's background color to use '$gray-05'
* replaced '$light-gray' references with '$gray-20'
* updated '<hr>' border color to '$gray-20'
* updated 'commitment' border color to '$gray-20'
* updated '.criterion' border color to '$gray-20'
* replaces '$medium-gray' references with '$gray-40'
* replaces '$dark-gray' references with '$gray-60'
* updated '.donate-modal' background to '$gray-80'
* added $red and $dark-red & replaced hex code used in SCSS files with the 2 colour variables
* Updated $blue and $dark-blue with the new color codes
* updated text link styling so it's using $dark-blue and is underlined when on hover
* Added 'out of date' notice to style guide page
* Updated hr-gradient to hr-emphasis
* Updated '.key-item' box shadow to border-bottom & updated the colour to '$gray-20'
* changed 'color-hex-length' linting rule to be 'long' so it's easier for devs to compare hex codes
* replaced '#ffffff' with '$white' and '#000000' with '$black'
* added comments to colorr.scss
* force Buyer's Guide links to use the old blues