Changed int32 to int64

Since February 2013, OSM uses 64bit identifiers. See http://wiki.openstreetmap.org/wiki/64-bit_Identifiers

I ran into a bug creating a multipolygon for several cities, since the node ids became negative. This fixes the issue.
Merge pull request #8 from marians/master

From in32 to int64 node IDs
Bugfix (realtions -> relations)
Adding import statement for sys
Merge pull request #10 from marians/master

Thanks for the fixes
BUGFIX: add obj to todo_stack not the tuple, closes GH-9

additional changes:
Only dive into multipolygon elements, drop all other members like
admin_centre, subarea, ...
BUGFIX: if clause not allowed with numpy arrays
Merge branch 'master' of git://github.com/werner2101/python-osm

Conflicts:
	src/osm/pyosm.py
Merge branch 'master' into py3