This commit adds support for at least some of the Serial boards with the
CH341 chipset, tested using a board from sparkfun as well as one from
Amazon.com

The code was rearranged some of the Claim code and added a VID:DID to Serial Type table that I use to map, such that I know some of these devices have multiple valid setups.

Support Begin/End/Begin - Change baud

Added code to support switching baud rates, or more particular be able to call end() and then call begin(...) with same or different baud rate.

Hopefully some support for also releasing DTR when the end is called.

WIP - Start support for the begin(baud, format)

Adding some support to the code to handle some of the different possible format capabilities.

In particualar trying to handle the parity, number of bits and number of stop bits.

hacked up test app, such that if you type in command line like:
"#9600, 7e1"

It will extract the 9600 as the new baud and try to use format 7e1.  I only hard coded a few of these in the test app (8n1, 7e1, 7e2, 8n2)...

Again work in progress.  Took me awhile tofigure out how to do this for ch341 boards as I did not see any documents or code that handled this.  So had to deduce it from differences in USB packets.