Remove use of String.intern().

Me, on the blackboard:

"I will not optimize code without using a profiler."
"I will not optimize code without using a profiler."
"I will not optimize code without using a profiler."
"I will not optimize code without using a profiler."
"I will not optimize code without using a profiler."
...

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

@@ -839,7 +839,7 @@ public class Mustache {
     /** A helper class for named segments. */
     protected static abstract class NamedSegment extends Template.Segment {
         protected NamedSegment (String name, int line) {
-            _name = name.intern();
+            _name = name;
             _line = line;
         }
         protected final String _name;