Icons tweaked #4469

- The "light" icon theme is now a little lighter, to increase contrast.
- Toolbox icons are now small.
- Buttons:
  - Buttons without labels which use icons as their only source of info regarding what the button does (e.g. the white-balance pipette button) use normal-sized icons.
  - Labeled buttons which use icons as an auxiliary source of information (e.g. Auto-Crop) now use small icons. Curve type icons are also small even though they have no labels.
- Colored circles are smaller.
- Curve type icons redesigned and small.
- Hand icons (when panning the preview) redesigned to have a clear outline regardless of background color.
- Magnifier icons redesigned to have a thinner magnifier frame and larger inner parts.
- Perspective, distortion and crop icons redesigned.
- Some small icons were missing the `-small` suffix, now renamed.

rtdata/images/themed/svg/gears-play.svg

@@ -37,7 +37,7 @@
      inkscape:current-layer="SVGRoot"
      inkscape:document-units="px"
      inkscape:cy="12"
-     inkscape:cx="12"
+     inkscape:cx="7.684729"
      inkscape:zoom="33.833333"
      inkscape:pageshadow="2"
      inkscape:pageopacity="0"
@@ -71,7 +71,7 @@
         <dc:format>image/svg+xml</dc:format>
         <dc:type
            rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
-        <dc:title></dc:title>
+        <dc:title />
         <dc:creator>
           <cc:Agent>
             <dc:title>Maciej Dworak</dc:title>
@@ -156,5 +156,5 @@
      inkscape:connector-curvature="0"
      id="Symbol-4-6-8"
      d="M 14,14.357876 V 11 L 22.925089,17.051146 14,23 v -3.298368 z"
-     style="display:inline;opacity:0.7;fill:#008000;fill-opacity:1;stroke:none;stroke-width:0.04999533" />
+     style="display:inline;opacity:1;fill:#008000;fill-opacity:1;stroke:none;stroke-width:0.04999533" />
 </svg>