color definition overrides and flexibility

[Lecraminos]

While it is possible to change the color definitions directly in the provided scss-files, it is not possible to override these settings from other scss-files outside of the framework before the actual @import-statement such as:
$white: #dddddd; @import "~themekit/src/scss/theme"

Please consider introducing the !default option to all color definitions.

Furthermore, it would be far more practical and complete, to derive further color declarations from these color definitions for use e.g. in the (still color-hard-coded) definitions for the left sidebar.