Remove deprecated Gradle features

gradle/helpProject.gradle

@@ -81,7 +81,7 @@ task indexHelp(type: JavaExec) {
 	
 	classpath = sourceSets.helpIndex.runtimeClasspath
 	
-	main = 'com.sun.java.help.search.Indexer'		
+	mainClass = 'com.sun.java.help.search.Indexer'
 
 	// tell the indexer where send its output	
 	args '-db', outputFile.absolutePath
@@ -131,7 +131,7 @@ task buildHelp(type: JavaExec, dependsOn: indexHelp) {
 	inputs.dir helpRootDir
 	outputs.dir outputDir
 
-	main = 'help.GHelpBuilder'		
+	mainClass = 'help.GHelpBuilder'
 	
 	args '-n', "${project.name}"	 		// use the module's name for the help file name
 	
@@ -169,7 +169,7 @@ task findUnusedHelp(type: JavaExec) {
 
 	inputs.dir helpRootDir
 
-	main = 'help.validator.UnusedHelpImageFileFinder'		
+	mainClass = 'help.validator.UnusedHelpImageFileFinder'
 
 	// args '-debug' // print debug info
 

gradle/processorProject.gradle

@@ -164,7 +164,7 @@ task sleighCompile (type: JavaExec) {
 	 
 	// define standard parameters for JavaExec
 	classpath configurations.sleighConfig
-	main = 'ghidra.pcodeCPort.slgh_compile.SleighCompile'
+	mainClass = 'ghidra.pcodeCPort.slgh_compile.SleighCompile'
 	
 	// Delay adding the directory argument until the first part of the execution phase, so
 	// that any extra args added by a project override will be added to the arg list before

gradle/root/jacoco.gradle

@@ -104,11 +104,9 @@ task jacocoReport(type: JacocoReport, group: 'Coverage reports') {
   
    reports {
       html {
-         enabled true
+         required
          destination new File(rootDir.absolutePath + "/jacocoReport")
       }
-      xml {
-         enabled false
-      }
+      xml { }
    }
 }

gradle/root/svg.gradle

@@ -62,7 +62,7 @@ task rasterizeSvg(type: JavaExec) {
 			files.push(file.toString())
 		}
 						
-		main = MAIN_CLASS
+		mainClass = MAIN_CLASS
 			
 		// Set up the entire arg list, minus the input files.
 		def argsList = ["-scriptSecurityOff",