Change folder logisim-defaults is located in

Changed the location that logisim-defaults is located in from the user's home directory, to the directory which the Logsim's .jar file is running from.

docs/automatic_library_import.md

@@ -1,14 +1,21 @@
 # Automatically Importing Logisim Libraries
 
 Logisim Evolution supports loading custom libraries at startup, contained in Logisim `.circ` files.
-To do this, create a directory in your **home directory** named `logisim-defaults` and insert any Logisim libraries you
-would like to load every time Logisim Evolution starts. **Every circuit must have a unique name, and must not be called
+
+To do this, create a directory named `logisim-defaults` in either:
+- The same directory as the `.jar` file which is executing Logisim ![Where the logisim-defaults folder goes, if executing from a JAR file.](img/logisim-defaults-jar.png)
+
+- Inside `/build/classes/java/`, if running from Gradle. ![Where the logisim-defaults folder goes, if running from Gradle.](img/logisim-defaults-build.png)
+
+Inside the `logisim-defaults`folder should be any `.circ` files which you would like to load automatically at startup.
+**Every circuit must have a unique name, and must not be called
 "main"**. This is to avoid conflicts caused by loading libraries with the same name.
 
+![An example of a CIRC file in the logisim-defaults folder](img/logisim-defaults-folder.png)
+
 Please note that any files added using the `logisim-defaults` folder are third-party,
 and therefore will need referencing for any projects you use them in.
 
 As of present, libraries are only automatically imported on *startup*. By creating a new file through the user interface,
 only built-in libraries will be imported.
 
-![Logisim-defaults](img/logisim-defaults.png)

src/main/java/com/cburch/logisim/gui/start/Startup.java

@@ -44,6 +44,8 @@ import java.awt.event.AWTEventListener;
 import java.awt.event.ContainerEvent;
 import java.io.File;
 import java.io.FilenameFilter;
+import java.net.URLDecoder;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -760,6 +762,11 @@ public class Startup implements AWTEventListener {
     System.exit(-1);
   }
 
+  private static String getProgramDirectory() {
+    var pathOfMainClass = new File(Main.class.getProtectionDomain().getCodeSource().getLocation().getPath());
+    return URLDecoder.decode(pathOfMainClass.getParentFile().getAbsolutePath(), StandardCharsets.UTF_8);
+  }
+
   private void doOpenFile(File file) {
     if (initialized) {
       ProjectActions.doOpen(null, null, file);
@@ -888,7 +895,7 @@ public class Startup implements AWTEventListener {
 
     // Load in any user-defined default circuit files
     var defaultLibraries = templLoader.loadCustomStartupLibraries(
-            System.getProperty("user.home") + File.separator + "logisim-defaults");
+            getProgramDirectory() + File.separator + "logisim-defaults");
 
     // load in template
     loadTemplate(templLoader, templFile, templEmpty);