Merge pull request #1 from liuliliujian/master

upgrade spymemcached from 2.5 to 2.8.4
mget空指针异常bugfix
Merge pull request #2 from lichenq/20130206_lichenq_mget_npe

mget空指针异常bugfix
upgrade spymemcached version from 2.8.4 to 2.8.11