15.5.0

• New boards:
  • Arduino Opta
  • AcSIP S76S
  • Sigma IC AGAFIA SG0
  • Big Tree Tech EBB42 V1.1
  • Nucleo G070RB
• Updated Arduino core to v2.4.0 (release notes)
• Updated Arduino-mbed core to v3.5.4 (release notes)
• Minor fixes and improvements