Tweak detect function to be faster
First attempt at Zeus auto-detection, prep for per-device settings
Test calculating a live hashrate
Minor changes in TUI and API output
Silence a gcc compiler warning
Link against libudev for easier Zeus device detection.

For the moment the Zeus driver is not using libusb for
actual I/O. Libudev allows us to associate /dev/ttyN entires
with specific usb bus:device IDs.
Add failsafe check to skip already in-use devices
Switch from direct serial I/O to libusb
Add Zeus usb detection information
Properly restore kernel driver (and /dev/* entries) on close
Zeus USB-UART chip will not accept baud rate change
Add live hash rate calculation debug output, fix usb uninit
Update the Zeus driver to support direct serial and libusb
Add additional piece of debug info to API
Fix libusb pipe logic thinko
Update Zeus documentation
Properly choose serial or libusb at startup
Merge branch 'zeus'

Major improvements and additions to Zeus driver.

Can now use libusb as well as direct serial I/O and
supports autodetection.