Add Ptr::to_option method
Update to stop unsolicited copying and mark methods as unsafe
Avoid range checks in HashMap::each()
Optimize the lookup of traits containing a given method

Currently, trait_info is a hashmap that allows a quick lookup of all
methods contained in a given trait, but we actually only use it to
lookup traits that contain a given method. Adjusting the map to support
the lookup we actually need gives a nice speed boost, reducing the time
required for the resolution step for librustc from ~2.6s to ~1.0s on my
box.
Correctly track the source of imports with the same name
Implement a lint mode to detect unnecessary allocations
Remove all unnecessary allocations (as flagged by lint)
core::rt: Rename WorkQueue methods, remove extra push method
core::rt: Put a lock on the work queue
core::rt: Add MessageQueue type

This is the queue used to send messages to Schedulers
core::rt: Queues MessageQueue and WorkQueue are cloneable
core:rt:: Rename LocalServices to Task
core::rt: Add Local trait
core::rt: Store Task as a ~ pointer
rt: Rename rust_initialize_global_state to rust_initialize_rt_tls_key
core::rt: Move some TLS functions from local_sched to local_ptr
core::rt: Move more TLS functionality into local_ptr
core::rt: Make local_sched a wrapper around Local
core::rt: Convert users of local_sched to Local trait
core::rt: Remove local_sched module