add standard cs_error_t error handler

this was prompted by the fact that calling CPG#send can sometimes result in :err_try_again, and we need to try again. But instead of handling it on just CPG#send, we handle it on all calls.
Handle exceptions from nested corosync function calls
update ffi-swig-generator

fix issue with callback structs and size_t
add a cpg chat example script
update ffi

was experiencing an issue, but i think it may have been my own fault. keeping the update anyway
add generic read_type and write_type methods to FFI::Pointer
add cmap service

needs specs