Allow baseDir parameter with sub-directory

Previously, specifying a baseDir with a value holding a sub-directory
would fail as only the first directory got created. This commit allows
baseDir to hold a sub-directory as well (e.g. something like 'foo/bar').

Fixes gh-81

CHANGELOG.adoc

@@ -7,6 +7,7 @@ order.
 
 === Release 1.0.0 (In progress)
 
+* https://github.com/spring-io/initializr/issues/81[#81]: allow baseDir parameter with sub-directories.
 * https://github.com/spring-io/initializr/issues/80[#80]: upgrade to Gradle 2.3.
 * https://github.com/spring-io/initializr/issues/62[#62]: add version range support.
 * https://github.com/spring-io/initializr/issues/75[#75]: migrate smoke tests to Geb.

initializr/src/main/groovy/io/spring/initializr/ProjectGenerator.groovy

@@ -190,7 +190,7 @@ class ProjectGenerator {
 	private File initializerProjectDir(File rootDir, ProjectRequest request) {
 		if (request.baseDir) {
 			File dir = new File(rootDir, request.baseDir)
-			dir.mkdir()
+			dir.mkdirs()
 			return dir
 		} else {
 			return rootDir

initializr/src/test/groovy/io/spring/initializr/ProjectGeneratorTests.groovy

@@ -211,6 +211,15 @@ class ProjectGeneratorTests {
 				.isMavenProject()
 	}
 
+	@Test
+	void customBaseDirectoryNested() {
+		def request = createProjectRequest()
+		request.baseDir = 'foo-bar/my-project'
+		generateProject(request).hasBaseDir('foo-bar/my-project')
+				.isJavaProject()
+				.isMavenProject()
+	}
+
 	@Test
 	void groovyWithMavenUsesJavaDir() {
 		def request = createProjectRequest('web')