Rename wxGrid::GetSelectionRange() to GetSelectedBlocks()

This seems to be more consistent with the existing functions and doesn't
create ambiguity with a grid range.

Also rename wxGridSelectionRange to just wxGridBlocks as, in principle,
this class could be used for iterating over any blocks, not just the
selected ones.

No changes in functionality, this is just a renaming.

src/generic/grid.cpp

@@ -10284,13 +10284,13 @@ bool wxGrid::IsInSelection( int row, int col ) const
     return m_selection && m_selection->IsInSelection(row, col);
 }
 
-wxGridSelectionRange wxGrid::GetSelectionRange() const
+wxGridBlocks wxGrid::GetSelectedBlocks() const
 {
     if ( !m_selection )
-        return wxGridSelectionRange();
+        return wxGridBlocks();
 
     const wxVectorGridBlockCoords& blocks = m_selection->GetBlocks();
-    return wxGridSelectionRange(blocks.begin(), blocks.end());
+    return wxGridBlocks(blocks.begin(), blocks.end());
 }
 
 wxGridCellCoordsArray wxGrid::GetSelectedCells() const