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/crossed-arrows-in.svg

@@ -26,7 +26,7 @@
      borderopacity="1.0"
      inkscape:pageopacity="0"
      inkscape:pageshadow="2"
-     inkscape:zoom="33.75"
+     inkscape:zoom="34.25"
      inkscape:cx="12"
      inkscape:cy="12"
      inkscape:document-units="px"
@@ -75,7 +75,7 @@
         <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>
@@ -112,19 +112,19 @@
      inkscape:groupmode="layer"
      inkscape:label="Layer 1">
     <path
-       style="display:inline;opacity:0.7;fill:#2a7fff;fill-opacity:1;stroke:none;stroke-width:0.0348262"
+       style="display:inline;opacity:0.9;fill:#2a7fff;fill-opacity:1;stroke:none;stroke-width:0.0348262"
        d="M 17.211202,6.8416774 23,6.0147076 18.038177,1.0528839 Z"
        id="path2876" />
     <path
-       style="display:inline;opacity:0.7;fill:#2a7fff;fill-opacity:1;stroke:none;stroke-width:0.0348262"
+       style="display:inline;opacity:0.9;fill:#2a7fff;fill-opacity:1;stroke:none;stroke-width:0.0348262"
        d="M 1.052887,6.0147071 6.8416789,6.8416795 6.0147103,1.0528839 Z"
        id="path2866" />
     <path
-       style="display:inline;opacity:0.7;fill:#2a7fff;fill-opacity:1;stroke:none;stroke-width:0.0348262"
+       style="display:inline;opacity:0.9;fill:#2a7fff;fill-opacity:1;stroke:none;stroke-width:0.0348262"
        d="M 18.038177,22.999997 23,18.038174 17.211202,17.211203 Z"
        id="path2864" />
     <path
-       style="display:inline;opacity:0.7;fill:#2a7fff;fill-opacity:1;stroke:none;stroke-width:0.0348262"
+       style="display:inline;opacity:0.9;fill:#2a7fff;fill-opacity:1;stroke:none;stroke-width:0.0348262"
        d="M 6.0147103,22.999997 6.8416801,17.211199 1.052887,18.038174 Z"
        id="path2893" />
     <path