FT2232C support

[JohnDMcMaster]

WIP. Current state:

• rx/tx works
• Limited flow control directions work
• No plan for very specific things like GPIO and EEPROM writes unless they come up in my target

TODO:

• Split out parser vs printer more cleanly (ex: add control requests to json)
• Review JSON format
• Make a libftdi printer. pyserial won't be sufficient as soon as something like GPIO or EEPROM write gets used. Maybe print warnings for non-printable directives in pyserial printer?

[JohnDMcMaster]

Target is using MPSSE...dammit this is going to get a lot more exciting than I was hoping