Include I/O voltage in board information

[rcjcooke]

PlatformIO has a great database of development boards and it would be great to be able to use that database for selecting a board in the first place. I'm currently considering switching boards and am looking for certain characteristics in the new development board I go for but I came across two problems:

1. The online selection tool (at platformio.com/boards) doesn't list the debug tool, just whether debug is supported or not, so I can't differentiate between those that have on-board debug and those that require me to purchase additional hardware.
2. The pio boards command (and online selector) doesn't show I/O voltage for the boards (presumably because that information isn't currently recorded by platformIO?). I would love for that to be available so that I can specifically select 5V as a requirement.

[ivankravets]

Please temporary use updated docs: http://docs.platformio.org/en/latest/plus/debugging.html#tools-debug-probes

[ivankravets]

1st request is implemented in https://platformio.org/boards

Also, see new updated registry for platforms and frameworks

[rcjcooke]

Thanks @ivankravets, that's great! I'm using it already.