Add a command to produce a self-contained executable JAR for a CLI app

A new command, jar, has been added to the CLI. The command can be
used to create a self-contained executable JAR file from a CLI app.

Basic usage is:

spring jar <jar-name> <source-files>

For example:

spring jar my-app.jar *.groovy

The resulting jar will contain the classes generated by compiling the
source files, all of the application's dependencies, and entries
on the application's classpath.

By default a CLI application has the current working directory on
its classpath. This can be overridden using the --classpath option.
Any file that is referenced directly by the classpath is always
included in the jar. Any file that is found a result of being
contained within a directory that is on the classpath is subject to
filtering to determine whether or not it should be included. The
default includes are public/**, static/**, resources/**,
META-INF/**, *. The default excludes are .*, repository/**, build/**,
target/**. To be included in the jar, a file must match one of the
includes and none of the excludes. The filters can be overridden using
the --include and --exclude options.

Closes #241

spring-boot-cli/pom.xml

@@ -33,6 +33,11 @@
 			<artifactId>spring-boot-dependency-tools</artifactId>
 			<version>${project.version}</version>
 		</dependency>
+		<dependency>
+			<groupId>${project.groupId}</groupId>
+			<artifactId>spring-boot-loader-tools</artifactId>
+			<version>${project.version}</version>
+		</dependency>
 		<dependency>
 			<groupId>jline</groupId>
 			<artifactId>jline</artifactId>
@@ -98,6 +103,12 @@
 			<artifactId>aether-util</artifactId>
 		</dependency>
 		<!-- Provided -->
+		<dependency>
+			<groupId>${project.groupId}</groupId>
+			<artifactId>spring-boot-loader</artifactId>
+			<version>${project.version}</version>
+			<scope>provided</scope>
+		</dependency>
 		<dependency>
 			<groupId>org.codehaus.groovy</groupId>
 			<artifactId>groovy-templates</artifactId>