Bring pygamer up to tier one status

[TDHolmes]

It was a planned tier one board and is labeled as such, but conversion isn't complete.

[ianrrees]

I've got a pygamer on the way, hoping to dig in to this early December

[ianrrees]

In #750, I've got the BSP just about updated. Having just spent a while working through all the examples, I do think it's a good platform for testing out the HAL, however PyGamers are getting fairly old now and are out of stock at Adafruit and DigiKey. I wonder if we should check with Adafruit to confirm they intend to keep producing PyGamer, before we make it a tier one board.

Edit to add: I made a post on the Adafruit forum to ask about PyGamer production.

[jbeaurivage]

Looks like it's not been obsoleted by Adafruit. I have no problem bringing it up to T1 because of its peripheral set. I think 6 T1 boards is probably enough, I prefer to keep the T1 list short and sweet, as not to overburden ourselves with every breaking change.

[jbeaurivage]

This will be accomplished with #766.