auto merge of #15619 : kwantam/rust/master, r=huonw

- `width()` computes the displayed width of a string, ignoring the width of control characters.
    - arguably we might do *something* else for control characters, but the question is, what?
    - users who want to do something else can iterate over chars()

- `graphemes()` returns a `Graphemes` struct, which implements an iterator over the grapheme clusters of a &str.
    - fully compliant with [UAX#29](http://www.unicode.org/reports/tr29/#Grapheme_Cluster_Boundaries)
    - passes all [Unicode-supplied tests](http://www.unicode.org/reports/tr41/tr41-15.html#Tests29)

- added code to generate additionial categories in `unicode.py`
    - `Cn` aka `Not_Assigned`
    - categories necessary for grapheme cluster breaking

- tidied up the exports from libunicode
  - all exports are exposed through a module rather than directly at crate root.
  - std::prelude imports UnicodeChar and UnicodeStrSlice from std::char and std::str rather than directly from libunicode

closes #7043

4 files changed, 5 insertions, 6 deletions

diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 0df2bb0f57c..c0fddcb2ae5 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -237,7 +237,7 @@ use str::{Str, StrSlice};
 use str;
 use string::String;
 use uint;
-use unicode::UnicodeChar;
+use unicode::char::UnicodeChar;
 use vec::Vec;
 
 // Reexports
diff --git a/src/libstd/path/windows.rs b/src/libstd/path/windows.rs
index 88ae0d4837e..02d9dc44489 100644
--- a/src/libstd/path/windows.rs
+++ b/src/libstd/path/windows.rs
@@ -24,7 +24,7 @@ use option::{Option, Some, None};
 use slice::{Vector, ImmutableVector};
 use str::{CharSplits, Str, StrAllocating, StrVector, StrSlice};
 use string::String;
-use unicode::UnicodeChar;
+use unicode::char::UnicodeChar;
 use vec::Vec;
 
 use super::{contains_nul, BytesContainer, GenericPath, GenericPathUnsafe};
diff --git a/src/libstd/prelude.rs b/src/libstd/prelude.rs
index a20ac112ac5..eee494c7bc0 100644
--- a/src/libstd/prelude.rs
+++ b/src/libstd/prelude.rs
@@ -59,7 +59,7 @@
 #[doc(no_inline)] pub use ascii::{Ascii, AsciiCast, OwnedAsciiCast, AsciiStr};
 #[doc(no_inline)] pub use ascii::IntoBytes;
 #[doc(no_inline)] pub use c_str::ToCStr;
-#[doc(no_inline)] pub use char::Char;
+#[doc(no_inline)] pub use char::{Char, UnicodeChar};
 #[doc(no_inline)] pub use clone::Clone;
 #[doc(no_inline)] pub use cmp::{PartialEq, PartialOrd, Eq, Ord};
 #[doc(no_inline)] pub use cmp::{Ordering, Less, Equal, Greater, Equiv};
@@ -77,7 +77,7 @@
 #[doc(no_inline)] pub use ptr::RawPtr;
 #[doc(no_inline)] pub use io::{Buffer, Writer, Reader, Seek};
 #[doc(no_inline)] pub use str::{Str, StrVector, StrSlice, OwnedStr};
-#[doc(no_inline)] pub use str::{IntoMaybeOwned, StrAllocating};
+#[doc(no_inline)] pub use str::{IntoMaybeOwned, StrAllocating, UnicodeStrSlice};
 #[doc(no_inline)] pub use to_str::{ToString, IntoStr};
 #[doc(no_inline)] pub use tuple::{Tuple1, Tuple2, Tuple3, Tuple4};
 #[doc(no_inline)] pub use tuple::{Tuple5, Tuple6, Tuple7, Tuple8};
@@ -89,7 +89,6 @@
 #[doc(no_inline)] pub use slice::{Vector, VectorVector};
 #[doc(no_inline)] pub use slice::MutableVectorAllocating;
 #[doc(no_inline)] pub use string::String;
-#[doc(no_inline)] pub use unicode::{UnicodeChar, UnicodeStrSlice};
 #[doc(no_inline)] pub use vec::Vec;
 
 // Reexported runtime types
diff --git a/src/libstd/rt/backtrace.rs b/src/libstd/rt/backtrace.rs
index d01a1b5b131..d075f9a1205 100644
--- a/src/libstd/rt/backtrace.rs
+++ b/src/libstd/rt/backtrace.rs
@@ -21,7 +21,7 @@ use os;
 use result::{Ok, Err};
 use str::StrSlice;
 use sync::atomics;
-use unicode::UnicodeChar;
+use unicode::char::UnicodeChar;
 
 pub use self::imp::write;