Cleanup dependencies (#201)

* We don't need to shadow in `lombok` itself. Gradle must be upgraded to at least 4.6 to support `annotationProcessor`, which is a version that still supports Java 7.
* `args4j-maven-plugin` is intended to use as a maven plugin.
* The requirement for `jaxb-api` was removed in 81cba7d58c0ce8a334204700dca669f2ad8e16ff
* We are only using `simple-xml`, don't need the whole `retrofit`+`okhttp`+`okio` chain.
* Resolve deprecation warnings in JNA code.

build.gradle

@@ -3,7 +3,7 @@ buildscript {
 		jcenter()
 	}
 	dependencies {
-		classpath 'com.github.jengelman.gradle.plugins:shadow:2.0.1'
+		classpath 'com.github.jengelman.gradle.plugins:shadow:4.0.4'
 	}
 }
 apply plugin: 'java'
@@ -19,20 +19,23 @@ compileJava {
 	options.compilerArgs << '-XDignore.symbol.file'
 }
 
+shadowJar {
+	exclude 'OSGI-OPT/'  // args4j garbage
+}
+
 repositories {
 	jcenter()
 	mavenCentral()
 }
 
 dependencies {
-	compile 'org.projectlombok:lombok:1.18.8'
-	compile 'org.kohsuke.args4j:args4j-maven-plugin:2.0.31'
-	compile 'net.lingala.zip4j:zip4j:1.3.2'
-	compile 'net.java.dev.jna:jna-platform:4.0.0'
-	compile 'net.java.dev.jna:jna:4.0.0'
-	compile 'javax.xml.bind:jaxb-api:2.3.1'
-	compile 'com.squareup.retrofit2:converter-simplexml:2.3.0'
+	compileOnly 'org.projectlombok:lombok:1.18.12'
+	annotationProcessor 'org.projectlombok:lombok:1.18.12'
 
+	compile 'args4j:args4j:2.33'
+	compile 'net.lingala.zip4j:zip4j:1.3.3'
+	compile 'net.java.dev.jna:jna-platform:5.0.0'
+	compile 'org.simpleframework:simple-xml:2.7.1'
 	implementation 'com.formdev:flatlaf:0.30'
 }