Fix and extend Response class.
Improve error handling in LocalFileSystem and it's sublasses and implement worker thread function.
Put Respone and Request in separated files.
Introduce ErrorResponse.
Minor fixes in Request and Response.
Add pure virtual Response::operator ().
Modify ErrorResponse constructor.
Put ReadDirectoryRequest, ReadDirectoryResponse and ReadDirectoryErrorResponse in read_directory.cpp/hpp files.
Add getters to Protocol::File.
Remove old code from LocalFileSystem.
Improve ErrorResponse and remove ReadDirectoryErrorResponse.
Introduce ResponseType and RequestType and update classes derived from Response and Request.
Tntroduce stub for ReadDirectoryRequest test.