Terminal escape color codes visible in output

[frewsxcv]

Steps to reproduce:

1. Click on https://is.gd/dFCpHI
2. Click on "nightly"
3. Press "run"
4. Notice output has escape color codes:

rustc 1.16.0-nightly (5d994d8b7 2017-01-05)
warning: enum is never used: `Foo`, #[warn(dead_code)] on by default
 �(B�[m--> <anon>:1:1�(B�[m
  �(B�[m|
1 �(B�[m| enum Foo {}�(B�[m
  �(B�[m| ^^^^^^^^^^^

warning: function is never used: `foo`, #[warn(dead_code)] on by default
 �(B�[m--> <anon>:3:1�(B�[m
  �(B�[m|
3 �(B�[m|   �(B�[mfn foo(x: Foo) {�(B�[m
  �(B�[m|  �(B�[m_^ �(B�[mstarting here...
4 �(B�[m| | �(B�[m    match x {}�(B�[m
5 �(B�[m| | �(B�[m}�(B�[m
  �(B�[m| |_^ �(B�[m...ending here

Program ended.