Rust: Update 1-25 for tip

Modifications to the first 25 to build with (6/21/2014) version of
rust.
Rust: Update 26-36 for tip

Update problems 26-36 to build with (6/21/2014) version of rust.
Rust: Update 37-40 for tip

Update the rest of the implemented problems to work with (6/21/2014)
version of rust.
Rust: 41