auto merge of #7269 : luqmana/rust/drop, r=thestinger

Finally rename finalize to drop.
Closes #4332.

diff --cc doc/tutorial.md
Simple merge

diff --cc src/libextra/arc.rs
Simple merge

diff --cc src/libextra/sync.rs
Simple merge

diff --cc src/librustc/middle/trans/base.rs
Simple merge

diff --cc src/librustc/rustc.rs
Simple merge

diff --cc src/libstd/task/spawn.rs
Simple merge

diff --cc src/libsyntax/parse/parser.rs
Simple merge