talksapp: Support Git Hub gists

[prashanthpai]

It'll be nice to support Git Hub gists such as this sample one.

And go-talks app on appspot can support one or both of these:

http://go-talks.appspot.com/gist.github.com/<owner>/<gist-id>

or

http://go-talks.appspot.com/gist.github.com/<owner>/<gist-id>#<file-reference-tag>

Why support gists ?

• Gists themselves are git repos and they do not draw too much attention unlike repos.
• Gists can be set as secret i.e only those with the link can access. Presenters working on a WIP draft will find this incredibly useful.

[prashanthpai]

@campoy What do you think ?