libsyntax: change token::to_str to take &Token
libsyntax: change token fns to take &Token
libsyntax: more minor cleanup
libsyntax: change Parser::unexpected_last to take &Token
libsyntax: change token_is_word to take &Token
libsyntax: change binop_to_str to be pure
ARM C ABI implementation
libsyntax: Remove a mutable field from the tests. rs=demuting
librustc: Implement a lint mode for mutable structures; deny by default. r=tjc
libcore: Move Cell to core and de-~mut core and std
test: De-~mut the test suite. rs=demuting
libsyntax: Stop parsing `~mut`
librustc: De-[mut] librustc (remove all mutable arrays). rs=demuting
test: De-[mut] (remove all mutable arrays from) the tests. rs=demuting
librustc: Make `&const [T]` mean the same thing as `&[const T]`
Add non-exhaustive check for match guards

Fix ICE while there is no remained arms after checking guards
Removed deprecated `str()` functions in int-template.rs and uint-template.rs
bench: Fix botched option dances. rs=demuting
doc: Remove references to mut fields. rs=demuting
auto merge of #5110 : pcwalton/rust/and-const, r=pcwalton

r? @brson