Rename open/init/close/release functions to standardised names

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Reimplement logging macros to use library context

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Add support for specifying sysfs device via device switch
Improve USB bootloading

 - Handle bridge chip detecting device in bootloader mode
 - Unallocate connection objects correctly
 - Handle udev re-assigning device number on reset

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Improve README documentation

Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>