Generalize stats from f64 to the Float trait
Use is_zero
Allow attributes in std::bitflags::bitflags!

The `std::bitflags::bitflags!` macro did not provide support for
adding attributes to the generated structure or flags, due to
limitations in the parser for macros. This patch works around the
parser limitations by requiring a `flags` keyword in the overall
`bitflags!` invocation, and a `static` keyword for each flag:

    bitflags!(
        #[deriving(Hash)]
        #[doc="Three flags"]
        flags Flags: u32 {
            #[doc="The first flag"]
            static FlagA       = 0x00000001,
            static FlagB       = 0x00000010,
            static FlagC       = 0x00000100
        }
    )
Add (unsafe) coercion from bits to std::bitflags

The intent of `std::bitflags` is to allow building type-safe wrappers
around C-style flags APIs. But in addition to construction these flags
from the Rust side, we need a way to convert them from the C
side. This patch adds a `from_bits` function, which is unsafe since
the bits in question may not represent a valid combination of flags.
Change std::io::FilePermission to a typesafe representation

This patch changes `std::io::FilePermissions` from an exposed `u32`
representation to a typesafe representation (that only allows valid
flag combinations) using the `std::bitflags`, thus ensuring a greater
degree of safety on the Rust side.

Despite the change to the type, most code should continue to work
as-is, sincde the new type provides bit operations in the style of C
flags. To get at the underlying integer representation, use the `bits`
method; to (unsafely) convert to `FilePermissions`, use
`FilePermissions::from_bits`.

Closes #6085.

[breaking-change]
Update multiple file use statement example

Update the example to make the usage of `pub mod foo;` much more
apparent, as well as using an example where setting the visibility of
the module is actually necessary.
auto merge of #13822 : EdorianDark/rust/master, r=cmr

New attempt to generalize stats, after #12606.
Since #12355 did not get merged, i want go get first get my change done and the try to fix sum.
auto merge of #13897 : aturon/rust/issue-6085, r=bjz

The `std::bitflags::bitflags!` macro did not provide support for
adding attributes to the generates structure, due to limitations in
the parser for macros. This patch works around the parser limitations
by requiring a `flags` keyword in the `bitflags!` invocations:

    bitflags!(
        #[deriving(Hash)]
        #[doc="Three flags"]
        flags Flags: u32 {
            FlagA       = 0x00000001,
            FlagB       = 0x00000010,
            FlagC       = 0x00000100
        }
    )

The intent of `std::bitflags` is to allow building type-safe wrappers
around C-style flags APIs. But in addition to construction these flags
from the Rust side, we need a way to convert them from the C
side. This patch adds a `from_bits` function, which is unsafe since
the bits in question may not represent a valid combination of flags.

Finally, this patch changes `std::io::FilePermissions` from an exposed
`u32` representation to a typesafe representation (that only allows valid
flag combinations) using the `std::bitflags`.

Closes #6085.
auto merge of #13960 : brandonw/rust/master, r=alexcrichton

Update the example to make the usage of `pub mod foo;` much more
apparent, as well as using an example where setting the visibility of
the module is actually necessary.
log: Use writeln!() instead of write!()

This was accidentally left out of the recent logging improvements.
auto merge of #13982 : alexcrichton/rust/more-logging, r=nikomatsakis

This was accidentally left out of the recent logging improvements.