Fix error format for relative imports

Hi there, thank-you for this great time-saving library!

I've made a little tweak to improve the output text for relative imports, and hope you find it useful `:)`

I'm sorry that I have not written a test for this, I was unable to really get to grips with how they work, but here is a before and after screenshot:

Before:
![screenshot from 2014-10-13 10 46 50](https://cloud.githubusercontent.com/assets/767671/4611849/7e266620-52bf-11e4-9856-bb57ab647baf.png)

After:
![screenshot from 2014-10-13 10 47 05](https://cloud.githubusercontent.com/assets/767671/4611850/83c52a08-52bf-11e4-8100-9e47ab7a63fa.png)

(I am still investigating why I am being told both `. should be before ..` and `.. should be before .`)