Added documentation for bintray configuration.

gradle-plugins/publish-utils/src/main/groovy/net/corda/plugins/BintrayConfigExtension.groovy

@@ -1,13 +1,44 @@
 package net.corda.plugins
 
 class BintrayConfigExtension {
+    /**
+     * Bintray username
+     */
     String user
+    /**
+     * Bintray access key
+     */
     String key
+    /**
+     * Bintray repository
+     */
     String repo
+    /**
+     * Bintray organisation
+     */
     String org
+    /**
+     * Licenses for packages uploaded by this configuration
+     */
     String[] licenses
+    /**
+     * Whether to sign packages uploaded by this configuration
+     */
     Boolean gpgSign
+    /**
+     * The passphrase for the key used to sign releases.
+     */
     String gpgPassphrase
+    /**
+     * The publications that will be uploaded as a part of this configuration. These must match both the name on
+     * bintray and the gradle module name. ie; it must be "some-package" as a gradle sub-module (root project not
+     * supported, this extension is to improve multi-build bintray uploads). The publication must also be called
+     * "some-package". Only one publication can be uploaded per module (a bintray plugin restriction(.
+     * If any of these conditions are not met your package will not be uploaded.
+     */
     String[] publications
+    /**
+     * Whether to test the publication without uploading to bintray.
+     */
     Boolean dryRun
 }

gradle-plugins/publish-utils/src/main/groovy/net/corda/plugins/PublishTasks.groovy

@@ -9,6 +9,9 @@ import org.gradle.api.Project
  * A utility plugin that when applied will automatically create source and javadoc publishing tasks
  * To apply this plugin you must also add 'com.jfrog.bintray.gradle:gradle-bintray-plugin:1.4' to your
  * buildscript's classpath dependencies.
+ *
+ * To use this plugin you can add a new configuration block (extension) to your root build.gradle. See the fields
+ * in BintrayConfigExtension.
  */
 class PublishTasks implements Plugin<Project> {
     void apply(Project project) {