Adding board defined analog and digital pin map.
Refactoring after new board pin maps. Do not need per sketch.
Adding pin mode access functions. Clean up code format.
Adding support for echo mode access and NULL help string.
Using board pin map.
More shell commands in CosaShell/CosaTelnetShell.

1. analogread vcc -- read power supply voltage
2. digitalread led -- read the led value
3. digitalwrite led|PIN value -- write pin value
4. pinmode led|PIN [input|output|pullup] -- display or set pin mode
5. uptime -- seconds since system start
6. stty [eol=CR|LF|CRLF] -- display or set tty mode
7. tone off -- silence tone
New build script; smoke test by building CosaBlink sketch with all board variants.