Travis CI integration
Added rake to Gemfile for Travis CI
add callbacks and fix new_recode? still true after saved.

I add callbacks before/after_create/save/update/destroy if it exists an instance method.
Not implemented specify by a class method.

I found a bug, new_recode? still true after saved.
clear cache for test

clear @_metadata
Travis CI integration
Added rake to Gemfile for Travis CI
Merge branch 'callback'
Merge branch 'master' of github.com:katsuyoshi/motion_data_wrapper