color theme step 4, menu

* CSS adjustments are now enqueued preventing heavy load
* less verbose js logging
* simplistic SASS/LESS like (client side!) blending of placeholders in
CSS; now able to define placeholders that link to the dynamic "paints"
used in the palette, for example variable $nxs_color_tier1_d points to
the dark variant of the color selected in the fly-out menu for tier1
* auto generated css classes are currently commented out (see
nxs_js_get_themecsstemplate_part1() function)
* the default set of colortypes is now set to "tier1", "tier2", "base1"
and "base2".
* removed old color selectors (divided in head, main and footer) in
favor of the new color theme
* the color pickers of the darker, lighter and delta are still there,
but hidden
* inline styling to center menu is now applied on the UL instead of DIV,
since the DIV resulted in horizontal scrolling