Cleanup, reformat, remove useless gpio settings

* Deleted some more useless commented out code.
* Reformatted some more code to 80 cols.
* Removed extraneous gpio info from struct mcp2210_pin_config as the
  MCP2210 already manges this part just fine.
Add info for creek format

* Improve the @file section of the mcp2210-creek.h comments and
  completely detail the encoding format there.
* README.md: Clarify the creek encoding and point to the comments in
  the header where it's fully detailed.
Revamp help output for userland util