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

SPD-classes/src/main/java/com/watabou/utils/Graph.java

@@ -0,0 +1,107 @@
+/*
+ * Pixel Dungeon
+ * Copyright (C) 2012-2015  Oleg Dolya
+ *
+ * Shattered Pixel Dungeon
+ * Copyright (C) 2014-2016 Evan Debenham
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+package com.watabou.utils;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.LinkedList;
+import java.util.List;
+
+public class Graph {
+
+	public static <T extends Node> void setPrice( List<T> nodes, int value ) {
+		for (T node : nodes) {
+			node.price( value );
+		}
+	}
+	
+	public static <T extends Node> void buildDistanceMap( Collection<T> nodes, Node focus ) {
+		
+		for (T node : nodes) {
+			node.distance( Integer.MAX_VALUE );
+		}
+		
+		LinkedList<Node> queue = new LinkedList<Node>();
+		
+		focus.distance( 0 );
+		queue.add( focus );
+		
+		while (!queue.isEmpty()) {
+			
+			Node node = queue.poll();
+			int distance = node.distance();
+			int price = node.price();
+			
+			for (Node edge : node.edges()) {
+				if (edge.distance() > distance + price) {
+					queue.add( edge );
+					edge.distance( distance + price );
+				}
+			}
+		}
+	}
+	
+	@SuppressWarnings("unchecked")
+	public static <T extends Node> List<T> buildPath( Collection<T> nodes, T from, T to ) {
+		
+		List<T> path = new ArrayList<T>();
+		
+		T room = from;
+		while (room != to) {
+			
+			int min = room.distance();
+			T next = null;
+			
+			Collection<? extends Node> edges = room.edges();
+			
+			for (Node edge : edges) {
+				
+				int distance = edge.distance();
+				if (distance < min) {
+					min = distance;
+					next = (T)edge;
+				}
+			}
+			
+			if (next == null) {
+				return null;
+			}
+			
+			path.add( next );
+			room = next;
+		}
+		
+		return path;
+	}
+	
+	public interface Node {
+		
+		int distance();
+		void distance( int value );
+		
+		int price();
+		void price( int value );
+		
+		Collection<? extends Node> edges();
+		
+	}
+}