Tabcontainer strip bgColor overlays border

[nonken]

When setting a bgcolor on the tab stripe it overlays the border between the tabs and the content

[nonken]

(In [14395]) added 1x1 #ccc colored gif to "fake" border between the tabs and the tab content, refs #7154

[nonken]

This fix works but is not a perfect solution. The tabStripe (bg behind tabs) needs refactoring since when in noBoxed mode you will have some issues with left and right border if you want a tabstripe higher than 2px with 2 different colors. You will miss a left and right border

[nonken]

(In [14396]) fixed CSS to allow setting bgColor on tabStripe, its not the most optimal fix and probaly needs some refactoring (see #7155) to save image loading, fixes #7154

[bill]

(In [14548]) Change TabContainer? so that line separating labels from content is specified as a border on the tab labels <div> rather than the tab content <div>.

This seems to be a cleaner design in general and removes the need for the fake border gif (rolling back [14395], refs #7154), and allowing specifying a background color for the tab strip.

Only works for tundra at the moments; other theme updates to follow.

This will be followed by a number of checkins from Nikolai to do:

• add tabStrip=true/false flag
• adding spacer <div> between tab labels and tab content
• updates for nihilo and soria to match above changes to tundra