Remove Signed trait and add SignedInt trait

The methods have been moved into Float and SignedInt

src/libtest/lib.rs

@@ -60,7 +60,7 @@ use std::io::fs::PathExtensions;
 use std::io::stdio::StdWriter;
 use std::io::{File, ChanReader, ChanWriter};
 use std::io;
-use std::num::{Int, FloatMath};
+use std::num::{Float, FloatMath, Int};
 use std::os;
 use std::string::String;
 use std::task::TaskBuilder;