Updated Gradle build version numbers and removed file based Guava dep…

…endency.

build.gradle

@@ -27,19 +27,20 @@ buildscript {
     }
     dependencies {
         classpath 'com.neenbedankt.gradle.plugins:android-apt:1.4'
-        classpath 'com.android.tools.build:gradle:1.2.3'
+        classpath 'com.android.tools.build:gradle:1.3.0'
     }
 }
 
 repositories {
     jcenter()
+    mavenCentral()
 }
 
 dependencies {
     compile fileTree(include: ['*.jar'], dir: 'libs')
-    compile 'com.android.support:appcompat-v7:21.0.3'
+    compile 'com.android.support:appcompat-v7:23.1.1'
     compile 'com.arasthel:asyncjob-library:1.0.3'
+    compile group: 'com.google.guava', name: 'guava', version: '18.0'
     apt 'com.bluelinelabs:logansquare-compiler:1.0.6'
     compile 'com.bluelinelabs:logansquare:1.0.6'
-    compile files('libs/guava-18.0.jar')
 }