Adding CI, fixing large arrays (#33)

Improvements:
- Increased CHUNK size as per miniz instructions
- Added tests for very large arrays in NPZ files
- Added some CI tests to catch issues across platforms
- Removed the internal IO streams in favor of just using stringstream
- NPZs can now be read from and written to memory

Bugfixes:
- Fixed an issue where very large arrays in NPZ files would throw an error
- Fixed a bug with mac builds due to deprecated APIs

Signed-off-by: Matthew Johnson <matthew@matthewajohnson.org>

Removing using namespace (#28)

Hotfixes/linux errors (#27)

* Addressing extended compiler warnings

* Fixing some issues on the Windows size

* Updating the changelog

Adding keys member (#25)

Hotfixes/int64 size (#24)

* Bug fix for integer shift size

* Bumping version

Addressing NPZ version bug + misc (#23)

Making CMake integration easier (#22)

Adding Unicode support (#21)

* Adding unicode

* All tests passing

* Bumping the version

* Adding C# + adding tests

* Adding to release notes

Hotfixes/missing comma (#20)

* Fixing a missing comma

* Bumping the version

Hotfix/suffix buffer size (#19)

* Minor robustness fixes

* Bumping version + notes

* Adding scalar tests and fixed a bug

* Adding to the notes