Upgrading to Swift 5

Adding a comment for travis fix

Bumping to 6.0.1

Updating the podspec

This is a major version upgrade because the swift 4.1 changes aren't backwards compatible

s/linkedin/plivesey in the README

Making the ChangeTime object thread safe (#46)

Currently, DataModelManager methods aren't thread safe because they use this object

Changing the CacheDelegate to not take generic funcs for setting mode…

…ls (#41)

This is a backwards incompatible change but it should be easy to migrate.
The reason for this change is: https://bugs.swift.org/browse/SR-3038

Small fix to the docs for API changes

Converting to Swift 3 (#38)

This keeps all the APIs the same as before and only updates the project.
In a future commit, we'll convert the APIs.

Upgrading the project to Swift 2.3 (#37)

This provides Carthage support