PyXRootD PyPI distribution and new declarative file access API for XRootD Client

The project described in this report is related to XRootD framework development. It was divided into two parts. First part was about publishing XRootD python bindings called PyXRootD to Python Package Index. This makes PyXRootD installation much easier and resolves problem with versioning. Second part was about creating new API for file operations, which are one of mainly used components of XRootD framework. Introduced API provides more readable and convenient way of using asynchronous functions available in XRootD. This report describes the motivation behind both parts of the project and their implementation