Rewrote array/list fetch-by-index using collectors.

That's what collectors are for. This also avoids the needless expense of doing
Integer.parseInt on every single key (the vast majority of which will not
actually be numbers), every single time we do a context lookup.

src/main/java/com/samskivert/mustache/Template.java

@@ -7,12 +7,8 @@ package com.samskivert.mustache;
 import java.io.IOException;
 import java.io.StringWriter;
 import java.io.Writer;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
-import java.util.List;
 import java.util.Map;
 
 /**
@@ -143,18 +139,7 @@ public class Template
                     }
                     // once we step into a composite key, we drop the ability to query our parent
                     // contexts; that would be weird and confusing
-                    String next = comps[ii].intern();
-                    Integer idx = toNumber(next);
-                    if (idx != null) {
-                        Object nextData = null;
-                        List<Object> c = toList(data);
-                        if (c != null && idx >= 0 && idx < c.size()) {
-                            nextData = c.get(idx);
-                        }
-                        data = nextData;
-                    } else {
-                        data = getValueIn(data, next, line);
-                    }
+                    data = getValueIn(data, comps[ii].intern(), line);
                 }
                 return checkForMissing(name, line, missingIsNull, data);
             }
@@ -184,30 +169,6 @@ public class Template
         return checkForMissing(name, line, missingIsNull, NO_FETCHER_FOUND);
     }
 
-    protected static List<Object> toList(Object obj) {
-        if (obj instanceof Collection) {
-            return new ArrayList<Object>((Collection) obj);
-        } else if (obj instanceof Iterator) {
-            Iterator<Object> it = (Iterator<Object>) obj;
-            List<Object> lst = new ArrayList<Object>();
-            while (it.hasNext()) {
-                lst.add(it.next());
-            }
-            return lst;
-        } else if (obj instanceof Object[]) {
-            return Arrays.asList((Object[]) obj);
-        }
-        return null;
-    }
-
-    protected static Integer toNumber(String value) {
-        try {
-            return Integer.parseInt(value);
-        } catch (NumberFormatException ex) {
-            return null;
-        }
-    }
-
     /**
      * Returns the value of the specified variable, noting that it is intended to be used as the
      * contents for a segment. Presently this does not do anything special, but eventually this