feat: add kotlin support (#896)

Co-authored-by: Joshua Chandler <joshchandler88@gmail.com>

test/android/app/build.gradle

@@ -17,6 +17,8 @@
 */
 
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-android-extensions'
 
 android {
     compileSdkVersion 29
@@ -51,4 +53,9 @@ dependencies {
     implementation 'com.android.support:appcompat-v7:26.1.0'
     testImplementation 'junit:junit:4.12'
     testImplementation 'org.json:json:20140107'
+
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+}
+repositories {
+    jcenter()
 }