Revert "Merge pull request mixxxdj#3902 from ronso0/skins-qss-icons"

return to 'image: url(..) no-repeat center center;' for most skin icons
to avoid unscaled, blurry icons when Mixxx is scaled >100% with the 'background: ..'
shorthand at the cost of a lot of squeezed icons for (Linux) users still having
broken libKIconthemes5 5.80 installed.
A patched version of that lib is in the Mixxx 'stable' ppa.

res/skins/Deere/sampler_text_row.xml

@@ -65,8 +65,8 @@
                 <SetVariable name="state_0_pressed">icon/ic_play_48px.svg</SetVariable>
                 <SetVariable name="state_0_unpressed">icon/ic_play_48px.svg</SetVariable>
                 <SetVariable name="state_1_text"></SetVariable>
-                <SetVariable name="state_1_pressed">icon/ic_play_48px.svg</SetVariable>
-                <SetVariable name="state_1_unpressed">icon/ic_play_48px.svg</SetVariable>
+                <SetVariable name="state_1_pressed">icon/ic_pause_48px.svg</SetVariable>
+                <SetVariable name="state_1_unpressed">icon/ic_pause_48px.svg</SetVariable>
                 <SetVariable name="left_connection_control"><Variable name="group"/>,cue_gotoandplay</SetVariable>
                 <SetVariable name="right_connection_control"><Variable name="group"/>,cue_default</SetVariable>
                 <SetVariable name="display_connection_control"><Variable name="group"/>,play</SetVariable>

res/skins/Deere/style.qss

@@ -309,14 +309,13 @@ WLibrary QLineEdit,
 QPushButton#LibraryPreviewButton {
   background: transparent;
   margin: 0px;
-  padding: 3px;
+  padding: 0px;
   border: 1px solid transparent;
   border-radius: 2px;
 }
 
 QPushButton#LibraryPreviewButton:!checked {
-  /* TODO ronso0 Restore once fixed lib linKIconThemes (vers. <..80) is in *ubuntu main repos */
-  /*image: url(skin:/../Deere/icon/ic_library_preview_play.svg);*/
+  image: url(skin:/../Deere/icon/ic_library_preview_play.svg);
 }
 
 QPushButton#LibraryPreviewButton:!checked:hover {
@@ -325,7 +324,7 @@ QPushButton#LibraryPreviewButton:!checked:hover {
 }
 
 QPushButton#LibraryPreviewButton:checked {
-  /*image: url(skin:/../Deere/icon/ic_library_preview_pause.svg);*/
+  image: url(skin:/../Deere/icon/ic_library_preview_pause.svg);
   background-color: #0f0f0f;
   border: 1px solid #006596;
 }
@@ -1739,7 +1738,7 @@ do not highlight either state. */
 
 /* Special case SamplerPlayButtonRepeating controls
   When sampler is playing, displays same play icon as normal, but
-  background is red instead of blue.
+  background is purple instead of blue.
 */
 
 #SamplerPlayButtonRepeating[value="1"] {

res/skins/LateNight/skin.xml

@@ -298,7 +298,7 @@
       <!-- ToDo ronso0 :: Unfortunately, variables are not considered here, yet ;)
           because the launch screen appears while the skin is parsed.
       image: url(skin:/style_<Variable name="scheme"/>/mixxx_logo.svg); -->
-      background: transparent url(skin:/palemoon/style/mixxx_logo.svg) no-repeat center center;
+      image: url(skin:/palemoon/style/mixxx_logo.svg);
       padding: 0;
       margin: 0px 2px 0px 2px;
       border: none;