Update Gradle plugin to work with Android Studio 3.3 Canary

Android Studio 3.1.4 Stable doesn't render layout previews in this project
for whatever reason. Switching to the latest 3.3 Canary release fixes the
issue without affecting Gradle scripts but requires the new Android Gradle
plugin to match the new Android Studio release.

This commit will be reverted once development on the feature is done.

build.gradle

@@ -7,7 +7,7 @@ buildscript {
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.1.4'
+        classpath 'com.android.tools.build:gradle:3.3.0-alpha07'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Fri Apr 06 21:32:27 MSK 2018
+#Thu Aug 28 15:18:36 CEST 2018
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.9-all.zip