Doesn't work for non-atom keys

[Omar Bahareth]

When used with non-atom keys, it will not substitute anything and simply treat the string as if it didn't exist:

iex(1)> Mustache.render("Hello {{person}}!", %{"person" => "John"})
"Hello !"

Correct behavior only when used with an atom key:

iex(2)> Mustache.render("Hello {{person}}!", %{:person => "John"})
"Hello John!"

[Omar Bahareth]

This was my fault, I copy pasted the version number from the README and ended up with 0.0.2. I submitted PR #11 to update the version number in the README to 0.3.0 for people who make the same mistake like I did.