Revert "Force ant and android studio to use Java7"

build.gradle

@@ -53,13 +53,10 @@ android {
         release.setRoot('build-types/release')
     }
 
-    compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_7
-        targetCompatibility JavaVersion.VERSION_1_7
-    }
-
-    lintOptions {
-        abortOnError false
+    android {
+        lintOptions {
+            abortOnError false
+        }
     }
 
     productFlavors {

project.properties

@@ -11,5 +11,3 @@
 target=android-22
 android.library.reference.1=owncloud-android-library
 android.library.reference.2=libs/android-support-appcompat-v7-exploded-aar
-java.source=7
-java.target=7