No trample on inline text links when using references (text is replaced)

For example,

[A github issue](https://github.com/gitterHQ/gitter/issues/1)

should return the text "A github issue" but instead is returns gitterHQ/gitter#1

Created by: trevorah

If we supported styling links to be like issues, commits and user mentions, then we could do some awesome stuff.

This would mean that our github activity feed items could be written in our native markdown, which means no more massive payloads and templates.

For example:

Would be:

[trevorah](https://github.com/trevorah) on develop
[fixed activity tip not ope...](https://github.com/trevorah/repo/commit/xyz1234)
[(compare)](https://github.com/trevorah/repo/commit/xyz1234...xyz1235)

And we would add the popovers etc correctly.

Created by: trevorah

And if we really wanted to go crazy, we could start supporting this as a way to show popovers for any link that supports embeds.

Just to note the workaround, you can add anything to the end of the URL like a / or #0 to make it behave properly as a inline link on Gitter.

[A github issue](https://github.com/gitterHQ/gitter/issues/1/)
[A github issue](https://github.com/gitterHQ/gitter/issues/1#0)

@MadLittleMods @trevorah thanks for work around and fun conversation thinking about where this can go.