Comply with latest rust-ansi-term

.travis.yml

@@ -6,6 +6,4 @@ install:
   - sudo apt-get install rust-nightly cargo
 script:
   - cargo build
-  - rustc --test src/exa.rs -o exa-test
-  - ./exa-test
-
+  - cargo test

src/exa.rs

@@ -89,7 +89,7 @@ fn exa(options: &Options, print_header: bool, string: String) {
     // results are cached.
 
     let lengths: Vec<Vec<uint>> = table.iter()
-        .map(|row| row.iter().map(|col| strip_formatting(col).len()).collect())
+        .map(|row| row.iter().map(|col| strip_formatting(col.clone()).len()).collect())
         .collect();
 
     let column_widths: Vec<uint> = range(0, options.columns.len())