Contains winapi like functions for Delphi compatibility

This unit is being created specifically for compatibility with Delphi. It contains selected functions that are included in the Delphi Windows unit. These functions are mostly abstract and implemented by the LCL interfaces.
For LCL users:
The functions can be used to make porting of Delphi applications easier and are not 100% emulating winapi functions, not even under windows. They were implemented and tested with some common Delphi libraries. The LCL contains many extra functions that the Delphi VCL does not have.
For example:
Instead of using the common windows functions SaveDC and RestoreDC use instead the Canvas.SaveHandleState and Canvas.RestoreHandleState.

Returns the scollbar position.
If the scrollbar is not visible, then the return value is 0.
Returns true, if the rectangle is empty
IsEmptyRect returns true, if the area of the rectangle described by ARect is empty, i.e. right coordinate is less than or equal to the left coordinate, or the bottom coordinate is less than or equal to the top coordinate

Move Left/Right by dx, Top/Bottom by dy. Return Top and Left are >= 0.