Implement #[deriving_eq] on tuple like structs
Get rid of structural records in libsyntax and the last bit in librustc.
Moved core::extfmt to core::private::extfmt

Needs a snapshot to remove stage0 extfmt export in core
librustc: Separate the rest of the trait bounds with `+` and stop parsing space-separated ones. rs=plussing
auto merge of #5069 : pcwalton/rust/plussing-2, r=pcwalton
auto merge of #5071 : luqmana/rust/derec, r=pcwalton

Rid libsyntax of records and get rid of the last piece in `librustc/front/test.rs`.
auto merge of #5068 : sethpink/rust/derive-eq-tuple-struct, r=catamorphism

Previously an unimplemented error was thrown when using #[deriving_eq] on tuple-like struct definitions.
Remove the last bits of structural records from tests/rustc/rusti/rustpkg.
librustc: De-mut resolve. rs=demuting
librustc: De-mut some of trans
librustc: De-mut trans. rs=demuting
librustc: Remove all mutable fields from librustc. rs=demuting
Cleanup, commenting, trivial renaming
bump up limit on monomorphization
librustc: Fix broken test.
auto merge of #5059 : Kimundi/rust/incoming, r=catamorphism

compiles-as-is, but needs a snapshot to remove the `stage0`ed extfmt export in core.

Closes #4750
auto merge of #5075 : luqmana/rust/derec, r=catamorphism

Now only `lib core/pipes.rs` has `#[allow(structural_records)]`. That can be removed after a snapshot.
auto merge of #5076 : pcwalton/rust/demuting, r=pcwalton
auto merge of #5077 : jbclements/rust/increase-monomorphization-depth-limit, r=catamorphism

It appears that using deriving_eq/auto_encode on ASTs bumps up against the "gee this looks like infinite unfolding" limit of 10 in monomorphization. Increasing it to 30 seems to solve this problem for me....

Also, commenting and a few renames.