Add option to disable Snap to Grid by default when we move the selection (fix #4153)

data/pref.xml

@@ -307,6 +307,7 @@
       <option id="doubleclick_select_tile" type="bool" default="true" />
       <option id="force_rotsprite" type="bool" default="false" />
       <option id="multicel_when_layers_or_frames" type="bool" default="true" />
+      <option id="snap_to_grid" type="bool" default="true" />
     </section>
     <section id="quantization">
       <option id="with_alpha" type="bool" default="true" />

data/strings/en.ini

@@ -1650,6 +1650,7 @@ frames, the transformation will be applied to all cels of the selected
 layers/frames. Without this option, multiple cels will be transformed
 only if you select multiple cels explicitly in the timeline.
 END
+snap_to_grid_selection = Snap To Grid when the option is enabled
 autotimeline = Show timeline automatically
 autotimeline_tooltip = <<<END
 Show the timeline automatically

data/widgets/options.xml

@@ -262,6 +262,8 @@
           <check text="@.move_on_add_mode" id="move_on_add_mode" tooltip="@.move_on_add_mode_tooltip" />
           <check text="@.select_tile_with_double_click" id="select_tile_with_double_click"
 		 pref="selection.doubleclick_select_tile" />
+          <check text="@.snap_to_grid_selection"
+                 pref="selection.snap_to_grid"/>
           <check text="@.force_rotsprite" id="force_rotsprite"
 		 pref="selection.force_rotsprite"/>
           <check text="@.multicel_when_layers_or_frames" id="multicel_when_layers_or_frames"

src/app/ui/editor/moving_pixels_state.cpp

@@ -441,7 +441,8 @@ void MovingPixelsState::onCommitMouseMove(Editor* editor,
   KeyAction action = m_editor->getCustomizationDelegate()
     ->getPressedKeyAction(keyContext);
 
-  bool snapToGrid  = m_editor->docPref().grid.snap();
+  bool snapToGrid = (Preferences::instance().selection.snapToGrid() &&
+                     m_editor->docPref().grid.snap());
   if (bool(action & KeyAction::SnapToGrid))
     snapToGrid = !snapToGrid;