gui: Convert UI to use Fragments

Change-Id: I7269604a1da72e6b22f4bbac31c1f5561660ccf5
Refs: #2646, #2667
diff --git a/app/build.gradle b/app/build.gradle
index 674060e..86267a6 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -3,7 +3,7 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 19
+    compileSdkVersion 21
     buildToolsVersion "21.1.2"
 
     defaultConfig {
@@ -130,7 +130,7 @@
 
 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
-    compile 'com.android.support:appcompat-v7:20.0.0'
+    compile 'com.android.support:appcompat-v7:21.0.3'
     compile 'com.android.support:support-v4:21.0.3'
 
     compile 'net.named-data:jndn:0.4'
@@ -141,5 +141,4 @@
     compile 'com.google.protobuf:protobuf-java:2.6.1'
 
     compile 'joda-time:joda-time:2.7'
-    compile 'commons-lang:commons-lang:2.6'
 }