Simple RPC interface for Arduino version 3.0.0

In this release:

• Support for const parameters.
• Support for C strings (char* and char const* a.k.a. const char*).
• Support for different types of I/O interfaces via plugins, e.g.,
  • Hardware serial.
  • Software serial (untested).
  • Wire (untested).
  • Ethernet (untested).
• Support for using multiple interfaces at the same time.
• Full API documentation.