Make "." be the CLI's default classpath

Previously, the default classpath was empty. Now, in the absence of the
user providing a classpath via the -cp option, the default classpath
will be ".". If the user does specify a classpath, the classpath that's
used will be exactly what they have specified, i.e. "." will no longer
be on the classpath unless specified by the user.

The app sample integration test has been updated to verify that "." is
only the classpath by default.

Fixes #115

spring-boot-cli/samples/app.groovy

@@ -7,7 +7,7 @@ class Example implements CommandLineRunner {
 	private MyService myService
 
 	void run(String... args) {
-		print "Hello " + this.myService.sayWorld()
+		println "Hello ${this.myService.sayWorld()} From ${getClass().getClassLoader().getResource('samples/app.groovy')}" 
 	}
 }
 

spring-boot-cli/src/main/java/org/springframework/boot/cli/command/ScriptCommand.java

@@ -276,7 +276,7 @@ public boolean isGuessDependencies() {
 
 		@Override
 		public String[] getClasspath() {
-			return NO_CLASSPATH;
+			return DEFAULT_CLASSPATH;
 		}
 
 		@Override

spring-boot-cli/src/main/java/org/springframework/boot/cli/compiler/GroovyCompilerConfiguration.java

@@ -31,7 +31,7 @@ public interface GroovyCompilerConfiguration {
 	/**
 	 * Constant to be used when there is no {@link #getClasspath() classpath}.
 	 */
-	public static final String[] NO_CLASSPATH = {};
+	public static final String[] DEFAULT_CLASSPATH = { "." };
 
 	/**
 	 * Returns the scope in which the compiler operates.

spring-boot-cli/src/main/java/org/springframework/boot/cli/compiler/GroovyCompilerConfigurationAdapter.java

@@ -82,7 +82,7 @@ public String[] getClasspath() {
 		if (this.options.has(classpathOption)) {
 			return this.options.valueOf(classpathOption).split(":");
 		}
-		return NO_CLASSPATH;
+		return DEFAULT_CLASSPATH;
 	}
 
 	@Override

spring-boot-cli/src/test/java/org/springframework/boot/cli/SampleIntegrationTests.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.cli;
 
 import java.io.File;
+import java.net.URI;
 
 import org.codehaus.plexus.util.FileUtils;
 import org.junit.BeforeClass;
@@ -48,7 +49,9 @@ public static void cleanGrapes() throws Exception {
 	@Test
 	public void appSample() throws Exception {
 		String output = this.cli.run("app.groovy");
-		assertTrue("Wrong output: " + output, output.contains("Hello World"));
+		URI scriptUri = new File("samples/app.groovy").toURI();
+		assertTrue("Wrong output: " + output,
+				output.contains("Hello World! From " + scriptUri));
 	}
 
 	@Test