Generics migration (#237)

* Generics migration

This attempts to migrate this library in the least invasive way by preserving as
much of the original API as possible. It does not change the tests in a
meaningful way nor does it attempt to upgrade any logic that can be simplified
or improved with generics. This is purely an API migration, and still requires a
lot of additional work to be fully ready.

* Fix a few broken tests around serialization

* Add v2 suffix

* Temporarily change mod name for testing

* Rename module to /v2

Merge pull request #205 from emirpasic/development

Fix in ArrayList.Contains function against nil values

Merge pull request #203 from emirpasic/development

Implements PriorityQueue and CircularBuffer

Merge pull request #202 from emirpasic/development

Implements queues, LinkedListQueue and ArrayQueue

Merge pull request #195 from emirpasic/development

Set operations: intersection, union, difference

Merge branch 'development'

Merge branch 'development'

Merge branch 'development'

Merge pull request #190 from emirpasic/development

Development

Merge pull request #188 from emirpasic/development

Switch to CircleCI