Signal level notification

此版本中的新功能：- 1.0.6. Fixed a indicator. - 1.0.5. Display WiFi signal strength in units of dbm, when WiFi monitor enabled. - 1.0.5. Fixed a bug that causes crashes. - 1.0.4. LTE support - 1.0.3. Fixed a bug that causes crashes. - 1.0.2. Added an option to display an signal strength in dbm units in the status bar. - 1.0.1. Fine-tuning icon images. - 1.0.0. First release