open #244
Fixing scroll issue in Inspector via flex layout;
Added new _archetypes.scss file for .l-flex* and .col styles;
moved .col and associated mixin out of _layout.scss
and into _archetypes;
open #90
IN-PROGRESS
To support desired edge-to-edge styling of Inspector pane;
Removed superflous .scss file;
Enhancements to splitter .scss to allow flush edging and
edge shadows;