fix kown bugs

1.Fix some bugs.

1. Increase the servo example.
2. added preamble length selection.
3. Fixed nullptr redefinition.

1.updated softSerial library, support to baudrate 57600
2.Update CubeCell relevant documents
3.updated library lorawan version
4.fixed library lorawanminimal
5.added example LoRaWan_CLASS_A_wakeOverTheAir
6.fix asr650x function analogReadmV()

1.fixed known bugs.
2.updated AT to rev1.3

1.fixed spi library.
2.updated to AT rev1.1.
3.fixed micros() bug.

• Added the second SPI support for ASR6502 based boards;
• Added the second I2C support for ASR6502 based board;
• Known bug fix;
• Modify board type with the part number in the Arduino tools menu.

• Fixe low power bug for ASR6502 series boards

• Known bug fix;
• Added ASR6502 support;
• Added some new sensors example;
• Added software serial function;
• Update AT support，added "AT+ChMask" to modify channelsmask;
• Fixed funciton millis(), micros().

• Added debug level option;
• Added uplink confirmed and unconfirmed option;
• Optimized code structure;
• Naming in Arduino style;
• Resolving conflicts with other library names;
• Added more sensor (third party) libraries;
• Added full region for EU868 bands;
• Fixed known bugs.