jgvariant-tool: New module.

Adds a command line tool that can read and (in the future) manipulate
GVariant-formatted files.

Change-Id: Icc92eb409a97e7cf72dfd7535f6a8b3587dd4a48
diff --git a/pom.xml b/pom.xml
index be9fd26..1ab4b48 100644
--- a/pom.xml
+++ b/pom.xml
@@ -37,6 +37,8 @@
     <module>jgvariant-core</module>
     <module>jgvariant-ostree</module>
 
+    <module>jgvariant-tool</module>
+
     <module>jgvariant-bom</module>
   </modules>