Add support for GCC9.3 on MSP430. Fixes #9.

[Andy4495]

Creat new MSP430 platform core "msp430gcc9" version 3.0.0 (fixes #9)

• Updates MSP430 compiler to GCC 9.3.1.11 -- the last version released by Texas Instruments
  • See https://www.ti.com/tool/MSP430-GCC-OPENSOURCE
  • This is not the latest version of GCC, but is significantly more up-to-date than GCC version 4.6.6 included with MSP430 core version 1.1.0
  • This version now supports C++11 and C++14 by default
    • C++17 and C++20 are supported, but need to be explicitly enabled using the appropriate -std command line option
    • See https://gcc.gnu.org/projects/cxx-status.html
  • Code compiled with this version will probably use more RAM and flash than code compiled using GCC 4.6.6

Update mspdebug tool to version 0.25 on MacOS (for both msp430 v1.1.0 and msp430gcc9 v3.0.0)

• mspdebug is used for uploading to MSP430 non-ET boards.
• Version 0.25 has been tested to work with MacOS 15 Sequoia