Context lines aren't shown if there are blank lines

[Wilfred]

$ cargo run sample_files/load_before.js sample_files/load_after.js
sample_files/load_after.js -- JavaScript
 10 var db = require("./db.js");                                            12 
 11 var models = require("./models.js");                                    .. 
 12                                                                         .. 
 13 var total = 0;                                                          13 var total = 0;

Both sides have var db and var models.

[Wilfred]

Fixed in 0.12 context display rewriting.