Tabs are now titled.
Also there's no more need to reclick on the gfi button during a multiple layers request:
    adding a layer, tick or untick one will automatically update the control's layers.
The tabs are now inserted just before the "+" tab instead of removing the "+" tab, adding the tab and then re-adding the "+" button.
However, sometimes tab's title won't show for an unknown reason, and it's impossible to remove the tab at the right of the "+" button (it will instantly create another one).
Also, show and hide function (that were in comment before) are removed. Because of the inheritance of the resultspanel from a Panel which contains show and hide functions, they were ambiguous and useless.
Fix trailing/leading whitespace/tabs

Improves readability, shrinks the diff against master
While here remove a trailing comma that would probably have broken on IE
Use a more meaningful message, and in english by default.
More trailing spaces/english tokens