Tightened up the code in Template._render_tags().
Tightened up the code in Template._render_tags().

* Used re.split() instead of re.search() to avoid string slicing.
* Used one "".join() instead of repeated string concatenation.
* Avoided duplicate logic on loop exit (i.e. output += template).

android-ia/platform_external_pystache,android-ia/platform_external_pystache