Fix race in NewUUID() (#64)

* Fixed race in NewUUID()

* Remove unnecessary variable

Add darkfeline's change to set ifname if no interface is found.

Merge pull request #38 from dmitris/go-mod

add go.mod file

Remove leftover comment.

Fix reamde to no longer say this is experimental.
The API is not going to change.

Remove leftover comment.

Fix reamde to no longer say this is experimental.
The API is not going to change.

Update .travis.yml

Change a UUID from []byte to [16]byte along with other API changes.

Change a UUID from []byte to [16]byte along with other API changes.

Update paths