Adding better block detection

Pulled the block finding code into its own function to eliminate a
recursion problem.

Test failure count dropped because lambdas are supported and I just
needed to update the spec.  Pull request mustache/spec#86 aims to add
bash support.  Until then, the testing script will fall back to using
perl.

34 failing tests

tests/partial.expected

@@ -1,3 +1,3 @@
 <h2>Names</h2>
-
   <strong>Tyler</strong>
+