Fixes and improvements (#132)

- Fix glitch when turning on WiFi: It would temporarily show "No networks found" right before starting the first scan.
- Fix spinner to use Assets.h
- Replace statusbar battery icons 
- Better statusbar icon for when WiFi is on but not connected
- Replace statusbar WiFi icons and Wifi Manage RSSI/lock icons
- Fix for crash when timer is null in I2cScanner
- Deprecate Spacer
- Fixes for toolbar layout (simplified)
- Improved ImageViewer app: center image and add filename text on the bottom
- Add LV debug params to sdkconfig.developer
- Disabled LV spinner, msgbox and window widgets. These have equivalents in Tactility.

Boards/Simulator/Source/hal/SimulatorPower.cpp

@@ -26,7 +26,7 @@ bool SimulatorPower::getMetric(Power::MetricType type, Power::MetricData& data)
             data.valueAsUint32 = 4032;
             return true;
         case CHARGE_LEVEL:
-            data.valueAsUint8 = 80;
+            data.valueAsUint8 = 100;
             return true;
     }