AdiumTabStyle: adjust the icon in vertical tabs when the indicator is shown.
AdiumTabStyle: scale the large image to fit the forced width.
Also fix its vertical centring.
AdiumTabStyle: fix the title overlapping the icon.
Cleaned up -titleRectForBounds's variables that were used in both horizontal and vertical calculations.
Prevent creating invisible windows. If a single-tab window's tab is dragged onto itself, it'll disappear from view because the window it dragged from is hidden.
Clear highlighted cells when dragging starts.

When automaticallyAnimates is NO, a cell that was highlighted as the drag started did not get reset when the drag completed.
Merge commit '1c6eaaecb51ad8595678d6b6fc86a11b34a5279a'

* commit '1c6eaaecb51ad8595678d6b6fc86a11b34a5279a':
  Clear highlighted cells when dragging starts.
  Prevent creating invisible windows. If a single-tab window's tab is dragged onto itself, it'll disappear from view because the window it dragged from is hidden.
  AdiumTabStyle: fix the title overlapping the icon. Cleaned up -titleRectForBounds's variables that were used in both horizontal and vertical calculations.
  AdiumTabStyle: scale the large image to fit the forced width. Also fix its vertical centring.
  AdiumTabStyle: adjust the icon in vertical tabs when the indicator is shown.

Conflicts:
	Source/PSMTabDragAssistant.m