Began work on GenerateMavenBom task

* Added it to the new :buildSrc project, along with a preliminary test.
* Updated .gitignore so that source code in the "edu.ucar.build" package isn't ignored

.gitignore

@@ -24,9 +24,12 @@ _compareTemp
 bin/
 *~
 
-# Ignore gradle stuff
+# Ignore the Gradle cache directory.
 .gradle/
+# Ignore the output that Gradle generates in the "build/" directories...
 build/
+# ...but not the source code in the "edu.ucar.build" package.
+!**/src/**/edu/ucar/build/
 
 # Ignore default content directory for mock servlets
 tds/src/content/

buildSrc/build.gradle

@@ -0,0 +1,34 @@
+apply plugin: 'groovy'
+
+apply from: "../gradle/dependencies.gradle"
+
+dependencies {
+    compile gradleApi()  // We're developing a custom task, so we need the Gradle API.
+
+    testCompile (libraries["spock-core"]) {
+        // The Gradle API drags in the bundled version of Groovy that Gradle ships with (localGroovy()) –
+        // see https://discuss.gradle.org/t/unable-to-force-gradle-to-use-groovy-2-0-0-for-the-project/7021.
+        // Spock drags in another Groovy as a transitive dependency.
+        //
+        // So, there are multiple candidate versions of the Groovy dependency. Ordinarily, this is no problem for
+        // Gradle; it bas version-conflict-resolution machinery to deal with it. However, localGroovy() is a special
+        // kind of dependency that doesn't participate in that resolution (again, see above URL).
+        //
+        // Once added to a configuration, localGroovy() will remain part of it no matter what. Furthermore, since
+        // localGroovy() is "special", Gradle will not consider a second, "normal" Groovy dependency to be in conflict
+        // with it. This can result in two different versions of Groovy in the same configuration, and ultimately
+        // errors like: "groovy.lang.GroovyRuntimeException: Conflicting module versions. Module [groovy-all is loaded
+        // in version 2.4.4 and you are trying to load version 2.4.1".
+        //
+        // Our solution is to explicitly exclude any other Groovy dependencies whenever localGroovy() is already part
+        // of the configuration.
+        exclude group: 'org.codehaus.groovy', module: 'groovy-all'
+    }
+}
+
+task foo << {
+    println rootProject?.name
+    println project?.name
+    println project?.parent?.name
+    println "$rootDir"
+}

buildSrc/src/main/groovy/edu/ucar/build/GenerateMavenBom.groovy

@@ -0,0 +1,18 @@
+package edu.ucar.build
+
+import org.gradle.api.publish.maven.tasks.GenerateMavenPom
+import org.gradle.api.tasks.TaskAction
+
+/**
+ *
+ *
+ * @author cwardgar
+ * @since 2016-01-16
+ */
+class GenerateMavenBom extends GenerateMavenPom {
+    @TaskAction
+    def generateBom() {
+        println "YAY!"
+        println "Project: $project"
+    }
+}

buildSrc/src/test/groovy/edu/ucar/build/GenerateMavenBomTest.groovy

@@ -0,0 +1,29 @@
+package edu.ucar.build
+
+import org.gradle.api.Project
+import org.gradle.api.Task
+import org.gradle.testfixtures.ProjectBuilder
+import spock.lang.Specification
+
+/**
+ *
+ *
+ * @author cwardgar
+ * @since 2016-01-16
+ */
+class GenerateMavenBomTest extends Specification {
+    def "DoIt"() {
+        setup:
+        ProjectBuilder builder = ProjectBuilder.builder().withName("GenerateMavenBomTest")
+        Project project = builder.build()
+
+        Task task = project.tasks.create(name: 'generateBom', type: GenerateMavenBom) {
+        }
+
+        when:
+        task.generateBom()
+
+        then:
+        true
+    }
+}