use proper style for add icon

core/img/actions/add.svg

@@ -1,10 +1,62 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<svg xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://www.w3.org/2000/svg" height="22" width="22" version="1.0" xmlns:cc="http://creativecommons.org/ns#" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:dc="http://purl.org/dc/elements/1.1/">
- <defs>
-  <linearGradient id="a" y2="45.69" gradientUnits="userSpaceOnUse" x2="24.139" gradientTransform="matrix(.53994 0 0 .53668 -1.7557 -1.7859)" y1="6.5317" x1="24.139">
-   <stop stop-color="#fff" offset="0"/>
-   <stop stop-color="#fff" stop-opacity="0" offset="1"/>
-  </linearGradient>
- </defs>
- <path opacity=".4" d="m8.5932 8.2152v-5.9948h5v5.9948h6v5.0052h-6v6h-5v-6h-6v-5.0052h6z" fill-rule="evenodd" stroke="url(#a)"/>
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   height="16"
+   width="16"
+   version="1.1"
+   id="svg2"
+   inkscape:version="0.48.3.1 r9886"
+   sodipodi:docname="add.svg"
+   inkscape:export-filename="add.png"
+   inkscape:export-xdpi="90"
+   inkscape:export-ydpi="90">
+  <metadata
+     id="metadata12">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs10" />
+  <sodipodi:namedview
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1"
+     objecttolerance="10"
+     gridtolerance="10"
+     guidetolerance="10"
+     inkscape:pageopacity="0"
+     inkscape:pageshadow="2"
+     inkscape:window-width="1301"
+     inkscape:window-height="744"
+     id="namedview8"
+     showgrid="false"
+     inkscape:zoom="14.75"
+     inkscape:cx="12.655895"
+     inkscape:cy="5.3587617"
+     inkscape:window-x="65"
+     inkscape:window-y="24"
+     inkscape:window-maximized="1"
+     inkscape:current-layer="svg2" />
+  <g
+     transform="matrix(-0.70710678,-0.70710678,0.70710678,-0.70710678,-724.84547,752.15918)"
+     id="g4">
+    <path
+       inkscape:connector-curvature="0"
+       id="path2989"
+       d="m 1.6360606,1040.8645 2.8284271,-2.8284 3.5355134,3.5355 3.5355339,-3.5355 2.828427,2.8284 -3.535534,3.5355 3.535555,3.5356 -2.828428,2.8284 -3.5355539,-3.5356 -3.5356917,3.5354 -2.8281118,-2.8281 3.5353763,-3.5357 z"
+       sodipodi:nodetypes="ccccccccccccc" />
+  </g>
 </svg>