Merge tag 'release-0.3.1' into incoming

release 0.3.1
Tutorial revisions (among other things, closes #2990).
Further revisions suggested by nmatsakis (#2990).
Move fail upcall into rust libcore.
Moved malloc and free upcalls into rust runtime.
Merge pull request #2884 from elliottslaughter/rust-upcalls

Move fail upcall into rust
Add rustrt wrapper functions to export list.
Merge pull request #2996 from elliottslaughter/fix-rustrt-build

Add rustrt wrapper functions to export list.
remove unneeded export local_data in task.rs (#2945)
Add task::spawn_unlinked and start migrating away from task::unsupervise
Add debug flag to turn off landing pads.
Fix and un-xfail task-killjoin-rsrc.rs
rustc: Make vtables use the coherence tables
syntax: Remove reference to typestate in a comment
Oops, xfail-win32 task-killjoin-rsrc
Merge pull request #3000 from dgryski/master

Fix formatting of multiline code blocks in asm-comments
Add Damian Gryski to AUTHORS
Adding simple net::url module to parse and format urls.
rustc: Max/min classes: Add struct literal syntax
Merge pull request #2998 from elliottslaughter/no-landing-pads

Add debug flag to turn off landing pads.