title: cant build gradle project after trying to add facebook SDK
body: <p>I tried adding facebook to my gradle file like this:</p>
  
  <pre><code>buildscript {
      repositories {
          maven { url 'http://download.crashlytics.com/maven' }
      }
  
      repositories { mavenCentral() }
  
      dependencies {
          classpath 'com.crashlytics.tools.gradle:crashlytics-gradle:1.+'
      }
  }
  
  
  apply plugin: 'com.android.application'
  apply plugin: 'crashlytics'
  
  repositories {
      maven { url 'http://download.crashlytics.com/maven' }
  }
  
  
  android {
      compileSdkVersion 22
      buildToolsVersion "21.1.3"
  
      defaultConfig {
          applicationId "com.beerportfolio.beerportfoliopro"
          minSdkVersion 15
          targetSdkVersion 21
          versionCode 59
          versionName "4.6.1"
      }
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
          }
      }
  }
  
  dependencies {
      compile fileTree(dir: 'libs', include: ['*.jar'])
      compile 'com.android.support:appcompat-v7:21.0.3'
      compile "com.android.support:appcompat-v7:21.0.+"
      compile 'com.google.android.gms:play-services:+'
      compile 'com.crashlytics.android:crashlytics:1.+'
  
  
  }
  </code></pre>
  
  <p>ALso in facebook directions it says:</p>
  
  <blockquote>
    <p>A note for Android developers If you are using ProGuard on the release
    build of your app, you must add this snippet to your app's
    proguard-project.txt config file:</p>
    
    <p>-keep class com.facebook.** { *; }
    -keepattributes Signature These flags are used to preserve generics signatures and to preserve type information used for reflection. Both
    flags are necessary for the SDK to function correctly in an Android
    app.</p>
  </blockquote>
  
  <p>So in my pro guard file (I may have done this in the wrong file..):</p>
  
  <pre><code># Add project specific ProGuard rules here.
  # By default, the flags in this file are appended to flags specified
  # in /Users/Mike/Documents/adt-bundle-mac-x86_64-20140321/sdk/tools/proguard/proguard-android.txt
  # You can edit the include path and order by changing the proguardFiles
  # directive in build.gradle.
  #
  # For more details, see
  #   http://developer.android.com/guide/developing/tools/proguard.html
  
  # Add any project specific keep options here:
  
  # If your project uses WebView with JS, uncomment the following
  # and specify the fully qualified class name to the JavaScript interface
  # class:
  #-keepclassmembers class fqcn.of.javascript.interface.for.webview {
  #   public *;
  #}
  
  -keep class com.facebook.** { *; }
  -keepattributes Signature
  </code></pre>
  
  <p>So when I try and build my project it throws this error:</p>
  
  <p><img src="https://i.stack.imgur.com/3aC0f.png" alt="enter image description here"></p>
  
  <p>And when I click that and try and fix it I get this:</p>
  
  <p><img src="https://i.stack.imgur.com/mlFUh.png" alt="enter image description here"></p>