fix #102, enable multidex

app/build.gradle

@@ -12,6 +12,7 @@ android {
         targetSdkVersion 25
         versionCode 51
         versionName "2.1.3"
+        multiDexEnabled true
     }
 
     signingConfigs {
@@ -36,6 +37,7 @@ dependencies {
     compile 'joda-time:joda-time:2.9.1'
     compile 'com.facebook.stetho:stetho:1.4.1'
     compile 'com.bignerdranch.android:recyclerview-multiselect:0.2'
+    compile 'com.android.support:multidex:1.0.1'
 
     compile 'com.google.code.gson:gson:2.8.0'
     compile('com.google.http-client:google-http-client-gson:1.22.0') {

app/src/main/kotlin/com/simplemobiletools/calendar/App.kt

@@ -1,10 +1,9 @@
 package com.simplemobiletools.calendar
 
-import android.app.Application
-
+import android.support.multidex.MultiDexApplication
 import com.facebook.stetho.Stetho
 
-class App : Application() {
+class App : MultiDexApplication() {
     override fun onCreate() {
         super.onCreate()
         Stetho.initializeWithDefaults(this)