customize thrift server thread pool for drpc server
1. add thread pool threads conf, default 64
2. add thread pool queue size limit and conf, default 128
make MultiScheme serializable
Merge remote-tracking branch 'xiao/storm-425'
update changelog
Call dissoc with apply to delete keys in the rest arguments
Merge pull request #428 from herberteuler/master

Fix issue #403
update changelog
add basic __hash__ method to all generated Thrift python objects
update changelog