UI enhancement fixes (#3222)

- Added min-width and min-height to Display Layout lines to allow
 easier selection and move when line is purely vertical or horizontal;
 - Fixed spacing, size and icon of overlay close button;

platform/commonUI/dialog/res/templates/overlay.html

@@ -24,7 +24,7 @@
     <div class="c-overlay__outer">
         <button ng-click="ngModel.cancel()"
            ng-if="ngModel.cancel"
-           class="c-click-icon c-overlay__close-button icon-x-in-circle"></button>
+           class="c-click-icon c-overlay__close-button icon-x"></button>
         <div class="c-overlay__contents" ng-transclude></div>
     </div>
 </div>