This class takes care of file manipulations on the server, as well creating new user
accounts, checking the login operation, and reading the user's directory contents.
Overriden doPost method accepts a serialized Query object, instantiates
it, submits it to it's database, and returns the results back to the
client as the Response.
main simply calls shutDownEngine which gives an alternate way to shut down
the AutoSubmitEngine Thread (by typing in the command line of the server:
java AutoSubmitEngine.
The SubmitQueryServlet is no longer in use by the BioQuery application and does not need
to be installed! This servlet received commands and Query objects from the client
in order to submit Querys from the server, rather than directly from the client.