#495 Replaced strerror with strerror_r
Add Eigen to source tree
Use internal Eigen
Add MPL2 license for Eigen
Add notes about third-party libraries included in Jubatus
install proxy-related headers only if zookeeper is enabled (fix #517)
#495 change buffer size from 256 to 1024
Stop Travis to install Eigen
Merge pull request #526 from jubatus/conditional-distrib-headers

install proxy-related headers only if zookeeper is enabled (fix #517)
Merge pull request #521 from jubatus/feature/strerror_is_thread_unsafe

#495 Replaced strerror with strerror_r
Merge branch 'include-eigen' into feature/coreset
Merge branch 'develop' into feature/coreset
regenerated with jubatus/develop