Upgrades & fixes

Using the crates.io version of the "log" fixes
```
   Compiling smtp v0.0.6 (https://github.com/amousset/rust-smtp#d2dfaca5)
/home/grank/.cargo/git/checkouts/rust-smtp-65a23a25db4b0233/master/src/lib.rs:135:43: 135:60 error: multiple matching crates for `log`
/home/grank/.cargo/git/checkouts/rust-smtp-65a23a25db4b0233/master/src/lib.rs:135 #![feature(phase)] #[phase(plugin, link)] extern crate log;
                                                                                                                            ^~~~~~~~~~~~~~~~~
note: candidates:
note: path: /usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblog-4e7c5e5c.so
note: path: /usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblog-4e7c5e5c.rlib
note: crate name: log
note: path: /var/build/byzon-rust/target/deps/liblog-b6110bc38225692d.rlib
note: crate name: log
/home/grank/.cargo/git/checkouts/rust-smtp-65a23a25db4b0233/master/src/lib.rs:135:43: 135:60 error: can't find crate for `log`
/home/grank/.cargo/git/checkouts/rust-smtp-65a23a25db4b0233/master/src/lib.rs:135 #![feature(phase)] #[phase(plugin, link)] extern crate log;
                                                                                                                            ^~~~~~~~~~~~~~~~~
error: aborting due to 2 previous errors
Could not compile `smtp`.
```

Also the latest Rust upgrades.