liburl: rename and move from_str to Url::parse_str.

url::from_str => url::Url::parse_str

The FromStr trait still works, but its confusing to have a from_str
free function that retuns a Result, while the regular from_str
returns an Option, hence the rename.

[breaking-change]
liburl: rename and move path_from_str to Path::parse_str.

url::path_from_str => url::Path::parse_str

The FromStr trait still works, but its confusing to have a path_from_str
free function that retuns a Result, while the regular from_str style
functions return an Option, hence the rename to indicate a Result.

[breaking-change]
liburl: remove redundant fields in Url.

url.path - Now a Path instead of a String.

To fix old code:
url.path => url.path.path
url.query => url.path.query
url.fragment => url.path.fragment

Not much point having the Path struct if it's not going to be used.

[breaking-change]
liburl: Simplify encoding/decoding using iterators.
liburl: Remove some unnecessary allocations.

Some signatures have changed from String to &str returns.

To fix, call to_string() on the returned value.

[breaking-change]
liburl: cosmetic test changes.
liburl: Generic input for {en,de}code.
vim: set Rust tab conventions
rustc: Reorder error and note message to reduce confusion.

Moved note after error to reduce confusion when the pair appears in the
middle of other errors. Closes #13279.
Remove entry_bcx from FunctionContext

We no longer need to refer to the entry block from arbitrary places, so
we can drop it from FunctionContext.
move lifetime suggestion note to after the error

Closes #15433.
Update RELEASES.txt

Fix Typos
Fix #15453
Improved example in the Guide

Fixes https://github.com/rust-lang/rust/issues/15452
auto merge of #15429 : kballard/rust/vim_tab_conventions, r=pcwalton
auto merge of #15431 : iliekturtles/rust/13279-error-msg-order, r=pcwalton

Moved note after error to reduce confusion when the pair appears in the
middle of other errors. Closes #13279.
Added num::Signed implementation to Ratio (squashed)
rustc: Remove CrateId and all related support

This commit removes all support in the compiler for the #[crate_id] attribute
and all of its derivative infrastructure. A list of the functionality removed is:

* The #[crate_id] attribute no longer exists
* There is no longer the concept of a version of a crate
* Version numbers are no longer appended to symbol names
* The --crate-id command line option has been removed

To migrate forward, rename #[crate_id] to #[crate_name] and only the name of the
crate itself should be mentioned. The version/path of the old crate id should be
removed.

For a transitionary state, the #[crate_id] attribute is still accepted if
the #[crate_name] is not present, but it is warned about if it is the only
identifier present.

RFC: 0035-remove-crate-id
[breaking-change]
rustc: Add a new codegen flag, -C metadata=foo

This metadata is used to drive the hash of all symbols in a crate. The flag can
be specified a multiple number of times

RFC: 0035-remove-crate-id
rustc: Modify crate loading to ignore versions

This commit modifies crate loading to purely work off a `crate_name` and nothing
else. This commit also changes the patterns recognized from `lib<foo>-*` to
`lib<foo>*` to accomodate the future renamings of output files.

RFC: 0035-remove-crate-id