Add tiled map, tilesheet configs etc

These are just XML so relatively git-friendly.  They're needed for the
game and should be syncronised to the version of the code so they
really ought to be checked in.

assets/templates/fountain.tx

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<template>
+ <tileset firstgid="1" source="../objectsprites.tsx"/>
+ <object type="1" gid="2" width="48" height="48">
+  <properties>
+   <property name="animframes" type="int" value="3"/>
+   <property name="assetpath" value="/obj/fountain.png"/>
+  </properties>
+ </object>
+</template>