Merge #188

188: Add UuidVersion to the prelude r=Dylan-DPC a=kinggoesgaming

**I'm submitting a ...**
  - [ ] bug fix
  - [x] feature enhancement
  - [ ] deprecation or removal
  - [ ] refactor

# Description
Add `UuidVersion` to the prelude.

# Motivation
With #181, `UuidVersion` is now stable, and as such can be used as part of the `prelude`

# Tests
N/A

# Related Issue(s)
#181, #166

src/lib.rs

@@ -204,7 +204,7 @@ pub enum UuidVersion {
     /// Special case for `nil` [`Uuid`].
     ///
     /// [`Uuid`]: struct.Uuid.html
-    Nil,
+    Nil = 0,
     /// Version 1: MAC address
     Mac = 1,
     /// Version 2: DCE Security

src/prelude.rs

@@ -20,13 +20,14 @@
 //!
 //! ## The core types
 //!
-//! [`uuid`]`::{`[`ParseError`], [`Uuid`], [`UuidVariant`]`}`: The fundamental
+//! [`uuid`]`::{`[`ParseError`], [`Uuid`], [`UuidVariant`], [`UuidVersion`]`}`: The fundamental
 //! types used in [`uuid`] crate.
 //!
 //! [`uuid`]: ../index.html
 //! [`ParseError`]: ../enum.ParseError.html
 //! [`Uuid`]: ../struct.Uuid.html
-//! [`UuidVariant`]: enum.UuidVariant.html
+//! [`UuidVariant`]: ../enum.UuidVariant.html
+//! [`UuidVersion`]: ../enum.UuidVersion.html
 
 #[doc(inline)]
-pub use super::{ParseError, Uuid, UuidVariant};
+pub use super::{ParseError, Uuid, UuidVariant, UuidVersion};