Returns a session cookie as a string.
def self.create_session_cookie(username, password)
begin
response = RestClient.post("#{Urls::MYEXPERIMENT_URL}/#{Urls::SESSION_URL}",
"<session><username>#{username}</username><password>#{password}</password></session>",
{:content_type => 'application/xml'} )
response.cookies
rescue Exception => e
raise "REST call to acquire workflow resource failed!\n" + e
end
end