patch for quakeml.py in master branch - fixes typo in momentTensor for method_id

There is a typo in quakeml.py in setting the method_id value.

MethodID -> methodID

Thanks,
Brad

diff --git a/obspy/core/quakeml.py b/obspy/core/quakeml.py
index 23efe6d..971ce45 100644
--- a/obspy/core/quakeml.py
+++ b/obspy/core/quakeml.py
@@ -826,7 +826,7 @@ class Unpickler(object):
          obj.filter_id = self._xpath2obj('filterID', mt_el)
          obj.source_time_function = self._source_time_function(mt_el)
          obj.data_used = self._data_used(mt_el)
- obj.method_id = self._xpath2obj('MethodID', mt_el)
+ obj.method_id = self._xpath2obj('methodID', mt_el)
          obj.category = self._xpath2obj('category', mt_el)
          obj.inversion_type = self._xpath2obj('inversionType', mt_el)
          obj.creation_info = self._creation_info(mt_el)