Fixed Drawing of DrawSheetStruct, so DrawSheetLabelStructs are only drawn if they are not being moved (fixes ugliness while moving PinSheets).

Added GetBoundingBox() for DrawNoConnectStruct, DrawBusEntryStruct. Removed old XOR method form DeleteStruct(). 

Refresh panel after Block move (otherwise, no-longer-dangling ends of e.g. HierLabels are still displayed)

to change the sheet.  there is no 'change' since the sheet is new, and the associated screen 
should either be loaded from the hierarchy or from a file. 

    KiCad installation.
  * how-to-build-kicad.txt deprecated.
  * how-to-build-for-windows.txt deprecated.