Model#update_attribute now uses the setter:

Previously had used write_attribute under the hood, and would not work
with users who had overridden the setter themselves.

[ fix #3075 ]
Include specs in gemspec.

[ close #3077 ]
Fix failing spec with dynamic attributes
Fix spec runs on non standard mongod ports.

[ fix #3068 ]
validate errors against the new instance after using Document#becomes
Update changelog
Fix broken spec
Don't hit db on method_missing if array doesnt respond.

[ fix #3081 ]
Don't fall through method missing on empty.

Contextual now includes the Queryable module methods onto criteria.

[ fix #3047 ]
Bump to rails 4 rc2
bump to activemodel 4 stable
multi-field pluck

[fixes #3109]
Update travis-ci image

related #3055
removing ruby-head from travis as it is erroring tests
change api update_attributes -> update

AR 4 has changed their api, as mongoid wants to be as compatible as possible,
would be nice to update the update api as well.
[fixes #2966]
Updating changelog
document.atomically can take multiple of the same operation. fixes #3057
Update changelog
add `mongoid:drop_undefined_indexes` rake task

removes indexes that exist in the database but aren't specified on the
models
Update changelog