Implement file upload support using content disposition.

This replaces our custom `GLHTTPServer` with hooks that should be merged inside of cyclone. Before I send a pull request for my cyclone branch for having it integrated into cyclone I would like to have some feedback from you on it.

To use this you should install cyclone from this branch: https://github.com/hellais/cyclone/tree/feature/hooks and to test the chunked file upload support you should use this branch of GLClient: https://github.com/hellais/GLClient/tree/feature/chunked_file_upload

Note: this is a requirement in order to implemented encrypted file upload.