Because the user can just use the 'select' method to retrieve the information
from shadir server.

Otherwise, all the connections would still alive and this is not a good
behavior.

Once we need to close the connections it is not possible to return the
content of getresponse method, the method read would return an empty
string instead of the correct data.

And also the data returned by shadir is a json content,
to reach a better usage of libnetworkcache the data returned must be
loaded by json library, in other words, it must be a list.

implemented the first version of upload and download methods. Upload is using both server already, shacache and shadir.