Revert "python: improve swig bindings"

This commit breaks our Houdini/Swig integration.
The root cause is that our swig version needs to be upgraded,
so pull this back for now.

This reverts commit 73b02b2.

Author: davvid

src/py/partio.i

@@ -41,16 +41,9 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 #define SWIG_PYTHON_2_UNICODE
 %}
 
-%include "std_pair.i"
 %include "std_string.i"
 %include "std_map.i"
 
-namespace std {
-  %template(StringMap) map<string, string>;
-  %template() pair<string, string>;
-}
-
-
 %{
 #include <Partio.h>
 #include <PartioIterator.h>
@@ -609,6 +602,7 @@ void merge(ParticlesDataMutable& base, const ParticlesData& delta, const std::st
  * it manually. To do this, simply use the empty template instantiation, that
  * is, %template with no name.
  */
+%template() std::map<std::string, std::string>;
 
 /* typemap to convert Python arguments into an attrNameMap std::map pointer. */
 %typemap(in) const std::map<std::string, std::string> * attrNameMap (std::map<std::string, std::string> temp) {