Fix crash when a device list is missing from specific device settings

If any of the device lists (bitwig, vst2, vst3) were empty or missing
from the config file it would result in a crash if parameters had
been defined for either knob1 or knob2.

pom.xml

@@ -8,7 +8,7 @@
   <artifactId>twister-sister</artifactId>
   <packaging>jar</packaging>
   <name>Twister Sister</name>
-  <version>2.0.1</version>
+  <version>2.0.2</version>
 
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

src/main/java/io/github/dozius/TwisterSisterExtension.java

@@ -511,6 +511,10 @@ private void setupSpecificDeviceKnob(String controlKey, TwisterKnob knob, Device
                                                                                                   TwisterKnob knob,
                                                                                                   OnOffColorSupplier colorSupplier)
   {
+    if (settings == null) {
+      return;
+    }
+
     for (final SettingType setting : settings) {
       if (setting.parameters().get(key) == null) {
         continue;

src/main/java/io/github/dozius/TwisterSisterExtensionDefinition.java

@@ -47,7 +47,7 @@ public String getAuthor()
   @Override
   public String getVersion()
   {
-    return "2.0.1";
+    return "2.0.2";
   }
 
   @Override