API: start certain enums from 1
API: start certain enums from 1

For enums describing direction & active state, event types etc. use 1
as the first value as it's easier to debug when all valid values are
different than in a zero-initialized data structure.

Signed-off-by: Bartosz Golaszewski <108de5fbc428215dc26df4468b48691526611148@gmail.com>

brgl/libgpiod,brgl/libgpiod,brgl/libgpiod,brgl/libgpiod