Reject names with null-bytes in NamedLock::create.

[ryanavella]

Currently it is possible to produce a panic on Windows with the following:

NamedLock::create("\0 foo");

(notice no .unwrap() is required)

There is also inconsistent behavior between platforms. On Windows the name "\0" is treated equivalent to an empty string, but on Unix "" is just fine while "\0" results in Err(Error::CreateFailed).

The simplest fix I can think of is to reject null-bytes altogether, in addition to \ and /. I think this is technically a breaking change, but a minor one.

[oblique]

Thanks! I will create a release in few days.

[oblique]

named-lock 0.3.0 is released! Thanks!