moved css to avoid img relative path issue after build

src/css/dialogs-manage-palettes.css

@@ -127,7 +127,7 @@
   cursor: pointer;
   width: 24px;
   height: 100%;
-  background: url('../../img/tools/pen.png');
+  background: url('../img/tools/pen.png');
   display: inline-block;
   background-size: 20px;
   background-repeat: no-repeat;
@@ -211,7 +211,7 @@
   width: 120px;
   height: 120px;
   cursor: pointer;
-  /*background-image:url(../../img/tools/eyedropper.png);*/
+  /*background-image:url(../img/tools/eyedropper.png);*/
 }
 
 .palette-manager-color-details {

src/css/toolbox-layers-list.css

@@ -6,7 +6,7 @@
 }
 
 .layers-title {
-  background-image: url('../../img/layers.svg');
+  background-image: url('../img/layers.svg');
   background-size: 22px;
   background-repeat: no-repeat;
   background-position: 97%;

src/css/toolbox-palettes-list.css

@@ -2,7 +2,6 @@
 }
 
 .palettes-title {
-  background-image: url('../img/layers.svg');
   background-size: 22px;
   background-repeat: no-repeat;
   background-position: 97%;