examples: Add example using Common structure

[RaulTrombin]

Actually it's using the common::Device as Common,
Suggest to import common::Device as Generic on devices.rs ( same we do for Ping1D and Ping360).

So we fast can implement:
undefined = Generic::new()

which will handle an .upgrade() to a newer strucutre based on .get_device_info, if the structure is available <(ping1,pin360,omni), error>.

[patrickelectric]

I don't follow, why not having just a common device creation in the ping1d example ? And move it to just an abstract device creation example.
This and the ping1d example, shares 90% of the code.