Add inverse hyperbolic functions
Remove re-exports from libcore/core.rc

Also fix up all the fallout elsewhere throughout core. It's really nice being
able to have the prelude.
Add ldexp and frexp functions
Remove unnecessary infinity check
auto merge of #6441 : alexcrichton/rust/issue-5531, r=luqmana

Also fix up all the fallout elsewhere throughout core. It's really nice being
able to have the prelude.

I'm not quite sure how resolution works with traits, but it seems to me like the public imports at the top-level of the core crate were leaking into the sub-crates, but that could also be working as intended. Regardless, things compile without the re-exports now.
auto merge of #6463 : bjz/rust/numeric-traits, r=thestinger

This is part of the numeric trait reform tracked on issue #4819
Use static string with fail!() and remove fail!(fmt!())

fail!() used to require owned strings but can handle static strings
now. Also, it can pass its arguments to fmt!() on its own, no need for
the caller to call fmt!() itself.
Fix cosmetics for fail!() calls