Find correct HLU layer in ArcGIS documents (CR19)

Ensure that the correct HLU layer, to be used by the tool, can be found
regardless of where it is located in the document content list (e.g.
below group layers, coverage annotation layers, etc).
Enable switching of HLU layers - common (CR31)

Enable the user to switch between different HLU layers, where there is
more than one valid layer in the current document/workspace.  This
commit contains the common (ArcGIS/MapInfo independent) files only.
Enable switching of HLU layers - ArcGIS (CR31)

Enable the user to switch between different HLU layers, where there is
more than one valid layer in the current document/workspace.  This
commit contains the ArcGIS files only.
Enable switching of HLU layers - MapInfo (CR31)

Enable the user to switch between different HLU layers, where there is
more than one valid layer in the current document/workspace.  This
commit contains the MapInfo files only.
Changes to version number and readme files

Change the version number in the assembly and installer and in the
readme files.