Added capability to specify return type
Adding changelog file
Added docs about getter and setters in the Proxmox class
Response type handling refactored
Custom credential functionality added
Merge pull request #1 from aotd1/master

Following PSR coding style standards recommendations
Solving merge conflict
Added more custom credentials for testing
Added one more test, improved docs and CONTRIBUTING.md
Merge branch 'master' into improve-travis-ci
Run PSR checks and unitTests local.
Add coverage report