add support for 1 mbps baud rate

[davided12]

I have the Sparkfun can bus shield and I'm tryng to connect to an ecu that works at 1 mbps. Unfortunately this library only supports baud rates up to 500 kbps. I'm sure that is easy to edit the library but I don't know how to do this.
Can you please have a look at this?

thank's
Davide

[wbadry]

@davided12 I landed on this page as I also wanted to get more baud rates to be supported. I came by
this fork which implemented it. I don't know why it is not merged so far.

[sinai1]

Hello, can i get 83.3K of baud rate?, can please help me?