Switch to minSdkVersion 11 and remove unnecessary appcompat in android client

Author: mythz

src/AndroidClient/android/build.gradle

@@ -9,7 +9,7 @@ android {
     buildToolsVersion "23.0.2"
 
     defaultConfig {
-        minSdkVersion 15
+        minSdkVersion 11
         targetSdkVersion 23
         versionCode 1
         versionName version
@@ -92,7 +92,6 @@ install {
 
 dependencies {
     compile 'com.google.code.gson:gson:2.4'
-    compile 'com.android.support:appcompat-v7:23.1.1'
     compile fileTree(include: '*.jar', dir: 'libs')
     testCompile 'junit:junit:4.11'
     testCompile 'org.mockito:mockito-core:1.9.5'