rustdoc: Strip methods correctly based on privacy

Beforehand the id of a method was the id of the 'self' argument, but this is not
the id which privacy was using (the id of the ast::method) struct, so by moving
the ids over to the privacy-target ones the methods are now stripped correctly.
Try to improve format! error messages

Instead of just saying "unterminated format string" and friends, instead print
information about what was expected and what was found.

Closes #9931
Fix struct field visibility and add enum field doc

Struct fields with inherited visibility were previously stripped.

Closes #9899
auto merge of #9932 : alexcrichton/rust/better-fmt-errors, r=cmr

Instead of just saying "unterminated format string" and friends, instead print
information about what was expected and what was found.

Closes #9931
doc (en & ja): remove mentions of type float, rust and rusti tools
auto merge of #9939 : sinma/rust/doc, r=alexcrichton

Recently, the float type, and the rust and rusti tools have been removed from master.

float replaced by f64 in code examples, removed mentions of float, f suffix, rust and rusti in explanations.

(+ some stupid things like rust -> Rust)
auto merge of #9941 : alexcrichton/rust/rustdoc, r=huonw

Beforehand the id of a method was the id of the 'self' argument, but this is not
the id which privacy was using (the id of the ast::method) struct, so by moving
the ids over to the privacy-target ones the methods are now stripped correctly.
auto merge of #9946 : sfackler/rust/enum-doc, r=alexcrichton

Struct fields with inherited visibility were previously stripped.

Closes #9899
Use __morestack to detect stack overflow

This commit resumes management of the stack boundaries and limits when switching
between tasks. This additionally leverages the __morestack function to run code
on "stack overflow". The current behavior is to abort the process, but this is
probably not the best behavior in the long term (for deails, see the comment I
wrote up in the stack exhaustion routine).
auto merge of #9834 : alexcrichton/rust/morestack, r=brson

This commit re-introduces the functionality of __morestack in a way that it was
not originally anticipated. Rust does not currently have segmented stacks,
rather just large stack segments. We do not detect when these stack segments are
overrun currently, but this commit leverages __morestack in order to check this.

This commit purges a lot of the old __morestack and stack limit C++
functionality, migrating the necessary chunks to rust. The stack limit is now
entirely maintained in rust, and the "main logic bits" of __morestack are now
also implemented in rust as well.

I put my best effort into validating that this currently builds and runs successfully on osx and linux 32/64 bit, but I was unable to get this working on windows. We never did have unwinding through __morestack frames, and although I tried poking at it for a bit, I was unable to understand why we don't get unwinding right now.

A focus of this commit is to implement as much of the logic in rust as possible. This involved some liberal usage of `no_split_stack` in various locations, along with some use of the `asm!` macro (scary). I modified a bit of C++ to stop calling `record_sp_limit` because this is no longer defined in C++, rather in rust.

Another consequence of this commit is that `thread_local_storage::{get, set}` must both be flagged with `#[rust_stack]`. I've briefly looked at the implementations on osx/linux/windows to ensure that they're pretty small stacks, and I'm pretty sure that they're definitely less than 20K stacks, so we probably don't have a lot to worry about.

Other things worthy of note:
* The default stack size is now 4MB instead of 2MB. This is so that when we request 2MB to call a C function you don't immediately overflow because you have consumed any stack at all.
* `asm!` is actually pretty cool, maybe we could actually define context switching with it?
* I wanted to add links to the internet about all this jazz of storing information in TLS, but I was only able to find a link for the windows implementation. Otherwise my suggestion is just "disassemble on that arch and see what happens"
* I put my best effort forward on arm/mips to tweak __morestack correctly, we have no ability to test this so an extra set of eyes would be useful on these spots.
* This is all really tricky stuff, so I tried to put as many comments as I thought were necessary, but if anything is still unclear (or I completely forgot to take something into account), I'm willing to write more!
Implement io::net::unix
Finish implementing io::net::addrinfo

This fills in the `hints` structure and exposes libuv's full functionality for
doing dns lookups.
Address a few XXX comments throughout the runtime

* Implement Seek for Option<Seek>
* Remove outdated comment for io::process
* De-pub a component which didn't need to be pub
Remove unbound pipes from io::pipe

This isn't necessary for creating processes (or at least not right now), and
it inherently attempts to expose implementation details.
Move rt::io::stdio from FileStream to a TTY

We get a little more functionality from libuv for these kinds of streams (things
like terminal dimentions), and it also appears to more gracefully handle the
stream being a window. Beforehand, if you used stdio and hit CTRL+d on a
process, libuv would continually return 0-length successful reads instead of
interpreting that the stream was closed.

I was hoping to be able to write tests for this, but currently the testing
infrastructure doesn't allow tests with a stdin and a stdout, but this has been
manually tested! (not that it means much)
Migrate Rtio objects to true trait objects

This moves as many as I could over to ~Trait instead of ~Typedef. The only
remaining one is the IoFactoryObject which should be coming soon...
Remove rt::io::support

This removes the PathLike trait associated with this "support module". This is
yet another "container of bytes" trait, so I didn't want to duplicate what
already exists throughout libstd. In actuality, we're going to pass of C strings
to the libuv APIs, so instead the arguments are now bound with the 'ToCStr'
trait instead.

Additionally, a layer of complexity was removed by immediately converting these
type-generic parameters into CStrings to get handed off to libuv apis.
Remove IoFactoryObject for ~IoFactory

This involved changing a fair amount of code, rooted in how we access the local
IoFactory instance. I added a helper method to the rtio module to access the
optional local IoFactory. This is different than before in which it was assumed
that a local IoFactory was *always* present. Now, a separate io_error is raised
when an IoFactory is not present, yet I/O is requested.
Don't attempt to export uv functions directly
Migrate the last typedefs to ~Trait in rtio

There are no longer any remnants of typedefs, and everything is now built on
true trait objects.