Gid rid of rspec deprecation warnings
Fix _destroy check on nested attributes.

When passed an array, only on a 1-n situation with nested attributes,
the attributes were not properly getting converted to a hash with
indifferent access.

[ fix #2911 ]
[ close #2912 ]
Fix deprecations in sessions spec
Don't memoize collection_name and database_name.

[ fix #2893 ]
[ fix #2857 ]
Enable public-facing dirty attribute methods to cope with field aliases

Changeable uses db field names internally but should also be able to handle
aliases given to its public-facing methods.
Update changelog
Fix chaining nil scopes
Ensure setters always return set value.

[ close #2603 ]
Move rvm to 2.0.0 by default
Only add _type to IdentityMap if using inherited class

#2697 was forcing _type on all classe when pushing to identityMap. We must use the _type on the selector
only when using subclasses.
[Fixes #2916]
many builder to use selector with type when needed

[Related #2916]
Update changelog
Allow cyclic relations to be mixed.

[ fix #2883 ]
Fix rspec deprecation
Migrating .rvmrc file to .ruby-version
Remove String#to_a extension.

[ fix #2903 ]
add count(true) option, to use limit on count

[Fixes #2927]
Refactor count
Move to latest RSpec expectation syntax.

Just to be ahead of the deprecation of should since it pollutes the
global object.
Force RSpec 2.13 and higher