Replace PNGs by SVGs (#3896)

- removes no longer needed SVG compounds
- Improves cap and join style icons

images/images.qrc

@@ -48,9 +48,9 @@
         <file>north_arrows/gpsarrow2.svg</file>
         <file>splash/splash.png</file>
         <file>composer/missing_image.svg</file>
-        <file>themes/default/cap_flat.png</file>
-        <file>themes/default/cap_round.png</file>
-        <file>themes/default/cap_square.png</file>
+        <file>themes/default/cap_flat.svg</file>
+        <file>themes/default/cap_round.svg</file>
+        <file>themes/default/cap_square.svg</file>
         <file>themes/default/console/iconClassConsole.png</file>
         <file>themes/default/console/iconClearConsole.png</file>
         <file>themes/default/console/iconCodepadConsole.png</file>
@@ -94,10 +94,9 @@
         <file>themes/default/grass_mapset_open.png</file>
         <file>themes/default/grass_mapset_search.png</file>
         <file>themes/default/histogram.svg</file>
-        <file>themes/default/join_bevel.png</file>
-        <file>themes/default/join_miter.png</file>
-        <file>themes/default/join_round.png</file>
-        <file>themes/default/join_style.svg</file>
+        <file>themes/default/join_bevel.svg</file>
+        <file>themes/default/join_miter.svg</file>
+        <file>themes/default/join_round.svg</file>
         <file>themes/default/locked.svg</file>
         <file>themes/default/lockedGray.svg</file>
         <file>themes/default/mAction.svg</file>
@@ -143,10 +142,10 @@
         <file>themes/default/mActionAlignVCenter.svg</file>
         <file>themes/default/mActionAllEdits.svg</file>
         <file>themes/default/mActionAnnotation.svg</file>
-        <file>themes/default/mActionArrowDown.png</file>
-        <file>themes/default/mActionArrowLeft.png</file>
-        <file>themes/default/mActionArrowRight.png</file>
-        <file>themes/default/mActionArrowUp.png</file>
+        <file>themes/default/mActionArrowDown.svg</file>
+        <file>themes/default/mActionArrowLeft.svg</file>
+        <file>themes/default/mActionArrowRight.svg</file>
+        <file>themes/default/mActionArrowUp.svg</file>
         <file>themes/default/mActionAtlasFirst.svg</file>
         <file>themes/default/mActionAtlasLast.svg</file>
         <file>themes/default/mActionAtlasNext.svg</file>
@@ -340,8 +339,7 @@
         <file>themes/default/mIconDelete.png</file>
         <file>themes/default/mIconDeselected.svg</file>
         <file>themes/default/mIconDropDownMenu.svg</file>
-        <file>themes/default/mIconEditable.png</file>
-        <file>themes/default/mIconEditableEdits.png</file>
+        <file>themes/default/mIconEditableEdits.svg</file>
         <file>themes/default/mIconExpand.png</file>
         <file>themes/default/mIconExpandSmall.svg</file>
         <file>themes/default/mIconExpression.svg</file>
@@ -379,7 +377,6 @@
         <file>themes/default/mIconRasterGroup.svg</file>
         <file>themes/default/mIconRasterLink.svg</file>
         <file>themes/default/mIconRasterLayer.svg</file>
-        <file>themes/default/mIconRenderingEnabled.svg</file>
         <file>themes/default/mIconSelectAdd.svg</file>
         <file>themes/default/mIconSelected.svg</file>
         <file>themes/default/mIconSelectIntersect.svg</file>
@@ -399,7 +396,6 @@
         <file>themes/default/north_arrow.png</file>
         <file>themes/default/diagramNone.svg</file>
         <file>themes/default/pie-chart.svg</file>
-        <file>themes/default/plugin.png</file>
         <file>themes/default/pluginExperimental.png</file>
         <file>themes/default/pluginDeprecated.png</file>
         <file>themes/default/propertyicons/action.svg</file>
@@ -461,10 +457,8 @@
         <file>themes/default/stars_full.png</file>
         <file>themes/default/styleicons/color.svg</file>
         <file>themes/default/symbologyAdd.svg</file>
-        <file>themes/default/symbologyDown.svg</file>
         <file>themes/default/symbologyEdit.png</file>
         <file>themes/default/symbologyRemove.svg</file>
-        <file>themes/default/symbologyUp.svg</file>
         <file>themes/default/sync_views.svg</file>
         <file>themes/default/text.svg</file>
         <file>themes/default/tracking.svg</file>