Provide functionality for add-on development

build.gradle

@@ -485,6 +485,9 @@ dependencies {
     // Built In Add-on Libraries
     implementation 'com.github.RPTools:maptool-builtin-addons:1.3'
 
+    // File watcher library to work around some inconsistencies with java.nio.file.WatchService
+    implementation 'io.methvin:directory-watcher:0.18.0'
+
     // For advanced dice roller
     implementation 'com.github.RPTools:advanced-dice-roller:1.0.3'
 }

src/main/java/net/rptools/maptool/client/AppPreferences.java

@@ -393,6 +393,15 @@ public class AppPreferences {
 
   public static final Preference<String> iconTheme = StringType.create("iconTheme", "Rod Takehara");
 
+  public static final Preference<String> externalAddOnLibrariesPath =
+      StringType.create("externalAddOnLibrariesPath", null);
+
+  public static final Preference<Boolean> externalAddOnLibrariesEnabled =
+      BooleanType.create("externalAddOnLibrariesEnabled", false);
+
+  public static final Preference<String> createAddOnParentDir =
+      StringType.create("createAddOnParentDir", System.getProperty("user.home"));
+
   static {
     // Used to be stored as separate components but now is one color. Add if not already there.
     if (prefs.get("trustedPrefixFG", null) == null) {