Fixes atomic operations on read-only attributes

https://github.com/mongoid/mongoid/issues/3612
more specs for bit and inc readonly
Require `active_support` before cherry-picking any modules
Use rspec 3 rc1
Merge pull request #3654 from deeeki/require_activesupport

Require `active_support` before cherry-picking any modules
Bump version to beta2
Use moped 2.0.0.rc1 on gemspec
Add check for mongodb_version on bitwise tests

[fixes #3609]
Merge pull request #3613 from fred/readonly-atomic

Don't allow atomic operations on read-only attributes
Add changelog for #3613

Also small cleanup
Add gemspec to 4.1.0 travis
Bump rspec in 4.1 gemfile
Organize travis file

also stop testing on jruby-head
Fix gemspec pat on rails41
add jruby options back, otherwise we get outofmemory issues
Force activemodel dependecy to 4.0.x

Mongoid 4.0.0 wont support activemodel 4.1.x, so we need to hard force that version for now
Dont test on rails 4.1 for now
Avoid extra query on touch

Use where instead of find to avoid an extra query on the .touch method.
[fixes #3583]
Add ActiveModel module instance methods to prohibited_methods list

[fixes #3620]
Validate method? and method= on create field

We need to validate if the name of the field collide with methods name
such foo? or foo= .

[fixes #3620]