update python module to match new client API; misc fix in browse.c; re-arrange CmakeLists.txt again
rename client API functions; use standard return/error codes
finish updating python module to use new client API
added get_schema_version command
if there are no services in list, list_services should still return successful
add schema functions to client API; misc code cleanup and memory safety
use halloc for avahi allocator
finish schema-related functions in python module; misc fixes in python module