Information about sim cards, network signal, neighboring cells.

For the dual sim phones Android API provided methods only for 7.0 and above (5.1/6.0 partialy).

For some dual sim phones can getting only information about 2 sim and signal strenght for active sim. (Tested on qualcomm 5.1)

For some devices can get information about 2 sim and signal stenght for 2 sim. (Tested on mtk 4.4)

Signal Strenght:
1) API - use standard android API
2) SYS API - use vendor API.
On some devices different calculation of signal strenght.
The SYS API method is more accurate for most devices.

- Calculation LTE band for the current and neighboring cells (Android 7.0+)
- Available dark theme. Can enable it in the settings.

Menu has option 'Debug', it print methods provided by vendor in log.

Permissions :
- READ_PHONE_STATE is required for get phone info, IMEI.
- ACCESS_COARSE_LOCATION is required for getting neighbor cells.