Converted ShatteredPD to Build from Gradle

Major Changes:
- Shattered now builds effortlessly either from gradle CLI or android studio
- Much better dependency management through gradle (although it's not really used atm)
- Separate PD-classes repo is now SPD-classes module within main repo

build.gradle

@@ -0,0 +1,14 @@
+buildscript {
+    repositories {
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:2.1.2'
+    }
+}
+
+allprojects {
+    repositories {
+        jcenter()
+    }
+}