auto merge of #19460 : steveklabnik/rust/conf_fixes, r=alexcrichton
Improve documentation of checked_* functions
Update comment to current file path for intrinsics
lldb: Fix pretty printer for nullable-opt enums with fat pointers.
gdb: Fix pretty printer for nullable-opt enums with fat pointers.
libcore: add `Rhs` input parameter to comparison traits
Test PartialEq multidispatch
Treat builtin bounds like all other kinds of trait matches. Introduce a simple hashset in the fulfillment context to catch cases where we register the exact same obligation twice. This helps prevent duplicate error reports but also handles the recursive obligations created by builtin bounds.
Correct various compile-fail tests. Most of the changes are because we
now don't print duplicate errors within one context, so I sometimes
had to break functions into two functions.
FIXME(#19481) -- workaround valgrind cleanup failure (but the code is nicer this way anyhow)
Fixed out of date comment on `copy_memory`
libtest: get rid of dependency to ToJson

deriving encodable + using json::PrettyEncoder removes the only ToJson trait implementation in the rust repository outside of libserialize
New Guide: Ownership

This replaces the previous "Lifetimes guide," since we are discussing
things from an owernship perspective now.
Remove outdated comment.

https://github.com/rust-lang/rust/pull/19472#issuecomment-65370278
Overload the `==` operator

- String == &str == CowString
- Vec ==  &[T] ==  &mut [T] == [T, ..N] == CowVec
- InternedString == &str
Replace `equiv` method calls with `==` operator sugar
Remove unused transmutes from tests
Fix fallout
Deprecate Equiv
rustdoc: Fixed a missing rendering of ForeignStaticItems.