Make a time test less flaky

This test was failing periodically on windows and other platforms, and in
debugging the issue locally I've found that the previous test was failing
at the assertion `ns0 <= ns1`. Upon inspecting the values, the two numbers were
very close to one another, but off by a little bit.

I believe that this is because `precise_time_s` goes from `u64` -> `f64` and
then we go again back to `u64` for the assertion. This conversion is a lossy one
that's not always guaranteed to succeed, so instead I've changed the test to
only compare against u64 instances.
doc: CSS: fix code fonts

Closes #10330.
doc: disable parser error highlighting + a few fixes

CodeMirror parser errors are related to #9873.
doc: add favicon to tutorial/manual

Since tutorial/manual files are stored on static.rust-lang.org, browsers
try to fetch the favicon from there while it should be retrieved from the
main domain.
doc: tidy up makefile rules
be more robust when removing download artifacts and remove bogus raise statement
Implemented BufWriter

Filled in the implementations of Writer and Seek for BufWriter. It
raises the io_error condition if a write cannot fit in the buffer.

The Seek implementation for MemWriter, which was incorrectly using
unsigned arithmatic to add signed offsets, has also been replaced.
auto merge of #10451 : zkamsler/rust/buf_writer, r=alexcrichton

I implemented BufWriter. I realize the use of conditions are on their way out for IO, but it does raise a condition if a write will not fit in the buffer for now.

I also replaced the seek code for MemWriter. It was adding the offset as a uint, which is unsound for negative offsets. It only happened to work because unsigned addition performs the same operation with two's complement, and sizeof(uint) <= sizeof(i64) so there was no (lack of) sign extension. I replaced this with computing an offset as an i64 and clamping to zero. I don't expect anyone will have use BufWriter with a byte buffer greater than 2^63 bytes any time soon.

@alexcrichton

Closes #10433
auto merge of #10447 : alexcrichton/rust/flaky-time-test, r=catamorphism

This test was failing periodically on windows and other platforms, and in
debugging the issue locally I've found that the previous test was failing
at the assertion `ns0 <= ns1`. Upon inspecting the values, the two numbers were
very close to one another, but off by a little bit.

I believe that this is because `precise_time_s` goes from `u64` -> `f64` and
then we go again back to `u64` for the assertion. This conversion is a lossy one
that's not always guaranteed to succeed, so instead I've changed the test to
only compare against u64 instances.
auto merge of #10421 : adridu59/rust/patch-www, r=alexcrichton

* Closes #10330
* Improves on #9873
* Adds favicon for tutorial files
auto merge of #10464 : gutworth/rust/snap-err, r=pnkfelix

...tatement
Add Window build directory to .gitignore
Implement native::IoFactory

This commit re-organizes the io::native module slightly in order to have a
working implementation of rtio::IoFactory which uses native implementations. The
goal is to seamlessly multiplex among libuv/native implementations wherever
necessary.

Right now most of the native I/O is unimplemented, but we have existing bindings
for file descriptors and processes which have been hooked up. What this means is
that you can now invoke println!() from libstd with no local task, no local
scheduler, and even without libuv.

There's still plenty of work to do on the native I/O factory, but this is the
first steps into making it an official portion of the standard library. I don't
expect anyone to reach into io::native directly, but rather only std::io
primitives will be used. Each std::io interface seamlessly falls back onto the
native I/O implementation if the local scheduler doesn't have a libuv one
(hurray trait ojects!)
auto merge of #10457 : alexcrichton/rust/native-io, r=brson

This commit re-organizes the io::native module slightly in order to have a
working implementation of rtio::IoFactory which uses native implementations. The
goal is to seamlessly multiplex among libuv/native implementations wherever
necessary.

Right now most of the native I/O is unimplemented, but we have existing bindings
for file descriptors and processes which have been hooked up. What this means is
that you can now invoke println!() from libstd with no local task, no local
scheduler, and even without libuv.

There's still plenty of work to do on the native I/O factory, but this is the
first steps into making it an official portion of the standard library. I don't
expect anyone to reach into io::native directly, but rather only std::io
primitives will be used. Each std::io interface seamlessly falls back onto the
native I/O implementation if the local scheduler doesn't have a libuv one
(hurray trait ojects!)
test: Clean up xfail-{fast,win32} tests

Rename {struct-update,fsu}-moves-and-copies, since win32
failed to run the test since UAC prevents any executable whose
name contaning "update". (#10452)

Some tests related to #9205 are expected to fail on gcc 4.8,
so they are marked as `xfail-win32` instead of `xfail-fast`.

Some tests using `extra::tempfile` fail on win32 due to #10462.
Mark them as `xfail-win32`.
test: Fix signal-exit-status on windows
rustpkg: Disable test suite on windows

sha1, version, util tests are still alive and they pass on win32.
test: Add xfail-win32 to two debug-info tests
doc: Fix example on Windows
auto merge of #10472 : klutzy/rust/cleanup-xfail, r=alexcrichton

Closes #10452.