Fixed error when link reference are inside blockquotes

When I trying to parse this (malformed) piece of markdown, it throws an error


    <img src="hola ke ase">

    > Let's fork this repo!
    >
    > [markdown][]
    >

    > [markdown]: https://github.com/evilstreak/markdown-js


Error:

    TypeError: Object #<Object> has no method 'replace'