Update error message on compile
Single curly braces instead of double are being used
libsyntax: Remove the `use foo = bar` syntax from the language in favor
of `use bar as foo`.

Change all uses of `use foo = bar` to `use bar as foo`.

Implements RFC #47.

Closes #16461.

[breaking-change]
Improve text of Option.unwrap()

Fixes #9099
Remove innapropriate string mutability section.

Fixes #14948
auto merge of #16575 : pcwalton/rust/import-foo-as-bar, r=aturon

of `use bar as foo`.

Change all uses of `use foo = bar` to `use bar as foo`.

Implements RFC #47.

Closes #16461.

[breaking-change]

r? @aturon
Explain EOF behavior in File.eof().

Fies #16239.
auto merge of #16578 : steveklabnik/rust/gh16239, r=pcwalton

Fies #16239.
auto merge of #16579 : steveklabnik/rust/gh9099, r=pcwalton

Fixes #9099
auto merge of #16580 : steveklabnik/rust/gh1498, r=pcwalton

Fixes #14948
auto merge of #16345 : EduardoBautista/rust/fix-error-message-in-guide, r=steveklabnik

Just some simple changes to the guide.
serialize/base64: Add XML-specific encodings
serialize/base64: Make from_base64 config-aware

This commit changes the signature of the main method in the FromBase64
trait, as the existing code did not take config into account and relied
on an assumptions that are not true for all configs (i.e. that every
Base64 charset uses `-` for 0x3e and `_` for 0x3f).

This change makes the base64 API more symmetric and allows for future
changes to `from_base64` to make it more RFC-compliant.

[breaking-change]