Remove footerSpan check for available columns on the right

This check is not convenient when you set the footerSpan before all
columns are created. Client implementation should deal with this case.
diff --git a/bundles/org.eclipse.rap.nebula.widgets.grid/src/org/eclipse/nebula/widgets/grid/GridColumn.java b/bundles/org.eclipse.rap.nebula.widgets.grid/src/org/eclipse/nebula/widgets/grid/GridColumn.java
index cb89212..4f14a6d 100644
--- a/bundles/org.eclipse.rap.nebula.widgets.grid/src/org/eclipse/nebula/widgets/grid/GridColumn.java
+++ b/bundles/org.eclipse.rap.nebula.widgets.grid/src/org/eclipse/nebula/widgets/grid/GridColumn.java
@@ -1093,15 +1093,11 @@
     }
   }
 
-  private void checkFooterSpan( String key, Object value ) {
+  private static void checkFooterSpan( String key, Object value ) {
     if( FOOTER_SPAN.equals( key ) ) {
-      if( !( value instanceof Integer ) ) {
+      if( !( value instanceof Integer ) || ( ( Integer )value ).intValue() < 1 ) {
         SWT.error( SWT.ERROR_INVALID_ARGUMENT );
       }
-      int footerSpan = ( ( Integer )value ).intValue();
-      if( footerSpan < 1 || parent.indexOf( this ) + footerSpan > parent.getColumnCount() ) {
-        SWT.error( SWT.ERROR_INVALID_RANGE );
-      }
     }
   }
 
diff --git a/tests/org.eclipse.rap.nebula.widgets.grid.test/src/org/eclipse/nebula/widgets/grid/GridColumn_Test.java b/tests/org.eclipse.rap.nebula.widgets.grid.test/src/org/eclipse/nebula/widgets/grid/GridColumn_Test.java
index 06a826c..eab0f5b 100644
--- a/tests/org.eclipse.rap.nebula.widgets.grid.test/src/org/eclipse/nebula/widgets/grid/GridColumn_Test.java
+++ b/tests/org.eclipse.rap.nebula.widgets.grid.test/src/org/eclipse/nebula/widgets/grid/GridColumn_Test.java
@@ -876,13 +876,6 @@
     column.setData( FOOTER_SPAN, Integer.valueOf( 0 ) );
   }
 
-  @Test( expected = IllegalArgumentException.class )
-  public void testFooterSpan_outOfRangeValue() {
-    GridColumn[] columns = createGridColumns( grid, 5, SWT.NONE);
-
-    columns[ 1 ].setData( FOOTER_SPAN, Integer.valueOf( 5 ) );
-  }
-
   @Test
   public void testFooterSpan() {
     GridColumn[] columns = createGridColumns( grid, 5, SWT.NONE);