Revert "More modifications for SDK 21 build"

This reverts commit 61dc8fec9d.

.travis.yml

@@ -3,8 +3,7 @@ language: android
 android:
   components:
     - build-tools-21.1.1
-    - android-21
-    - extra-android-support
+    # Don't have any other tools so far, robolectric covers pretty much everything...
 
 script:
   - ./gradlew test

build.gradle

@@ -7,8 +7,6 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        // Version lock the gradle plugin because Kotlin only works with up to 14.2
-        // KT-6181 is open to track this issue
         classpath 'com.android.tools.build:gradle:0.14.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         // NOTE: Do not place your application dependencies here; they belong