add missing layer to maps

assets/tiled/base.tmx

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="11" nextobjectid="3">
+<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="12" nextobjectid="3">
  <properties>
   <property name="id" type="int" value="1"/>
  </properties>
@@ -487,6 +487,7 @@
    </properties>
   </object>
  </objectgroup>
+ <objectgroup id="11" name="Collectibles"/>
  <objectgroup id="8" name="Spawnpoints">
   <object id="1" x="2081" y="2330">
    <properties>

assets/tiled/level_fruehling.tmx

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="11" nextobjectid="3">
+<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="12" nextobjectid="3">
  <properties>
   <property name="id" type="int" value="1"/>
  </properties>
@@ -487,6 +487,7 @@
    </properties>
   </object>
  </objectgroup>
+ <objectgroup id="11" name="Collectibles"/>
  <objectgroup id="8" name="Spawnpoints">
   <object id="1" x="2081" y="2330">
    <properties>

assets/tiled/level_herbst.tmx

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="11" nextobjectid="3">
+<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="12" nextobjectid="3">
  <properties>
   <property name="id" type="int" value="1"/>
  </properties>
@@ -487,6 +487,7 @@
    </properties>
   </object>
  </objectgroup>
+ <objectgroup id="11" name="Collectibles"/>
  <objectgroup id="8" name="Spawnpoints">
   <object id="1" x="2081" y="2330">
    <properties>

assets/tiled/level_sommer.tmx

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="11" nextobjectid="3">
+<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="12" nextobjectid="3">
  <properties>
   <property name="id" type="int" value="1"/>
  </properties>
@@ -487,6 +487,7 @@
    </properties>
   </object>
  </objectgroup>
+ <objectgroup id="11" name="Collectibles"/>
  <objectgroup id="8" name="Spawnpoints">
   <object id="1" x="2081" y="2330">
    <properties>

assets/tiled/level_winter.tmx

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="11" nextobjectid="3">
+<map version="1.9" tiledversion="1.9.1" orientation="orthogonal" renderorder="right-down" width="64" height="64" tilewidth="64" tileheight="64" infinite="0" nextlayerid="12" nextobjectid="3">
  <properties>
   <property name="id" type="int" value="1"/>
  </properties>
@@ -487,6 +487,7 @@
    </properties>
   </object>
  </objectgroup>
+ <objectgroup id="11" name="Collectibles"/>
  <objectgroup id="8" name="Spawnpoints">
   <object id="1" x="2081" y="2330">
    <properties>