Cactoos version: 0.43 - released in 05/12/2019

Scope status:

1. Convert status testing assertions to EO ones [30%]
1. Use `Sliced` decorator to compose decorators which uses collection slicing (HeadOf, TailOf, etc) [40%]
1. Qulice update [100%] 
1.  Fix Rultor x Travis x Appveyor build results [100%]
1. Collections rethinking [0%]

Issues:

1. Cactoos and cactoos-matchers have circular dependencies that must be fixed. I suggest merging the projects again.
1. 0crat is taking more than 10 days to remove issues from performers, which is causing some slow in reassigning work from users that abandoned project but didn't quit it formally. 

Risks
1. Low REV and QA staff delay deliveries [3/3]
