Merge pull request #18 from den-zv/feature/provide_multiple_sort_desc…

…riptors

Update FetchRequest for support of multiple sort descriptors

Merge pull request #16 from Yalantis/feature/swift-5-update

[update] specify swift version

[remove] .swift-version

Merge pull request #14 from Yalantis/feature/remove-all-objects

Feature/remove all objects

Merge pull request #12 from Yalantis/feature/sync-operations

Feature/sync operations

Merge pull request #10 from Yalantis/feature/update

Feature/update

Merge pull request #5 from Yalantis/feature/update-bolts

[Update] bolts dependency

Merge pull request #4 from Yalantis/swift-4.1-fix

Fix segmentation fault error

Merge pull request #2 from Yalantis/feature/swift-4-support

Feature/swift 4 support