core: Add a rand::Rand trait that is implemented by types that can be
randomly generated
Also adds Rng::gen() for generating any type that implements the Rand
trait
testsuite: Add test for #4523
mk: Parameterize tests.mk to the max
mk: Don't check core/std/rustc as part of check-fast

When debugging check-fast it's annoying to wait through core/std
libsyntax: no binary/hex float literals
got rid of last empty lines
`core::send_map` renamed to `core::hashmap`

Encountered this while trying to port rustsqlite to rust 0.6
mk: Add output files to tests so they don't rerun unnecessarily
rt: Add rust_try_get_current_task
Make foreign calls work outside of tasks. #4451
Rewrite the exchange allocator to work without an active scheduler. #4457
remove issue #3148 workarounds (no longer needed)
treemap: get rid of some implicit vector copies
get rid of implicit vec copies in treemap iterator

Each call to next() was doing a copy rather than a move. There's
currently no way for this to be a method that uses &mut self, so it has
to be a free function. Closes #4763.
update treemap FIXME
treemap: make map_next and set_next public
remove old snapshot workaround from smallintmap
doc: improvements to version-stamp makefile logic.
Convert fuzzy_epsilon constant to upper case and make public
auto merge of #4801 : z0w0/rust/randomtrait, r=graydon

Also adds Rng::gen() for generically generating any type that implements the Rand trait. There's no way to generate things with a length (for e.g. strings or vectors), because I can't think of an elegant way to do that. Maybe have a RandLen trait that inherits Rand?

This can be used for a quickcheck mechanism I'm working on.