[library] another take at duplicate persistent requests
[library] delete the tape file if corrupted
Merge pull request #3 from eyeem/issue_2

[library] delete the tape file if corrupted
[eyeem-sdk] mission item endpoint
[library] add API for modifying Request params on add()
[eyeem-sdk] add support for staging api endpoints
[DON’T merge] changes to work as a submodule