Prefix subprojects with 'smack-'

instead of using the old baseName=smack appendix=project.name approach,
we are now going convention over configuration and renaming the
subprojects directories to the proper name.

Having a prefix is actually very helpful, because the resulting
libraries will be named like the subproject. And a core-4.0.0-rc1.jar is
not as explicit about what it actually *is* as a
smack-core-4.0.0-rc1.jar.

SMACK-265

smack-bosh/build.gradle

@@ -0,0 +1,14 @@
+description = """\
+Smack BOSH API.
+This API is considered beta quality."""
+
+repositories {
+	maven {
+		url 'https://oss.sonatype.org/content/repositories/snapshots'
+	}
+}
+
+dependencies {
+	compile project(':smack-core')
+	compile 'org.igniterealtime.jbosh:jbosh:0.8.0'
+}