Fix uniqueness validation for inherited models.
Expanding the query cache keys with limit, skip and fields
Fixing cache issue on querying all / first with same selector
Add comment to query_cache method
Update QueryCache spec

to show need for including the "skip" value in the cache key
Merge pull request #3561 from knapo/fix_uniquness_validation_for_inheritance

Fix uniqueness validation for inherited models.
Without :cursor / :first in cache key spec fails

running `rspec spec/mongoid/query_cache_spec.rb`

"Mongoid::QueryCache when querying in the same collection with same
selector when querying only the first queries again"

will throw following error:

"no implicit conversion of String into Integer"
Adding :first / :cursor context to the cache key

With this change, the previous failing spec is solved.
Allow fields to be reset to default values.

[ close #3580 ]
Fix localized fields with missing attributes.

[ fix #3568 ]
Bit changed behaviour
Don't send empty sets
Fix bad hint specs
Fix scope docs
Merge pull request #3562 from zenjoy/fix/query-cache

Expanding the query cache keys with limit, skip and fields
Use svg travis badge [skip ci]
Replace string evaluation with regular Ruby code
Revert "Bit changed behaviour"

This reverts commit 453142f5c668242a9b1ea33e6d596ef4a579a888.
Reverts 'd12bb528a729d9e6247954e0f5baaf0b31402d59'

Reverts spec/mongoid/contextual/atomic_spec.rb
Use final 4.1.0