Retrieves an (inverted) color from the given theme, will fall back
to the default theme.

@param {string} name
@param {object} props
@param {bool}   inverted

@return {string}
function getColor(name, props) {
    const t = getThemeOrDefault('colors', props);

    if (props && props.inverted) {
        const invertedName = `${name}Inverted`;

        if (invertedName in t) {
            const alphaName = `${invertedName}Alpha`;
            return createColor(t[invertedName], t[alphaName] || 1);
        }
    }

    if (name in t) {
        const alphaName = `${name}Alpha`;
        return createColor(t[name], t[alphaName] || 1);
    }

    return '#000000';
}