Added exports for messages, labels and adddresses

and some code improvements

exports/build.gradle

@@ -0,0 +1,23 @@
+uploadArchives {
+    repositories {
+        mavenDeployer {
+            pom.project {
+                name 'Jabit Exports'
+                artifactId = 'jabit-exports'
+                description 'Import and export data to JSON files.'
+            }
+        }
+    }
+}
+
+dependencies {
+    compile project(':core')
+    compile 'org.slf4j:slf4j-api'
+    compile 'com.beust:klaxon'
+
+    testCompile 'junit:junit:4.12'
+    testCompile 'org.hamcrest:hamcrest-library:1.3'
+    testCompile 'com.nhaarman:mockito-kotlin:1.5.0'
+    testCompile project(path: ':core', configuration: 'testArtifacts')
+    testCompile project(':cryptography-bc')
+}