Merge pull request #20 from duellsy/develop

Develop
Merge pull request #23 from duellsy/develop

Mocking for testing
Merge pull request #25 from duellsy/develop

Refactoring to use common base
Merge pull request #26 from duellsy/develop

Update readme.md
Merge pull request #29 from duellsy/develop

Develop
Fix #12 handle tag api calls

tag_rename still not implemented. Pocket generating 500 status code for
such requests