Update T3000

1. Fix the bug when the products doesn't have the serial number set up properly the node can show up in the database many times. Now only shows up once. 
2. Improve communications performance using cache, now the displays for online status, recent screens and so on will be cached on the local drive. Background refresh will update the data to real time info after the initial screen is splashed. 
3. Modify the Ranges  user interface, add custom digital range for user defined binary inputs.
4. Add PTP feature for GSM connections and slow serial port connections (not finished)