Added Support for ghost asset based content discovery.

[djmittens]

Perhaps there is a much better way to handle this but this is m attempt at supporting Ghosts asset based handlebars anontation.

Goal to support handebars expressions such as:
{{asset "js/normalize.css"}}

• I decoupled the actual render string from the string used for configuration of destinations.
• Added some ignores for my ide of choice

Hardcoded to expect {{asset Not the best way to solve the problem generically but i feel that was way out of scope for the changes that i needed.

Changed the regular expressions to be able to handle spaces inside of the replace path.

[sindresorhus]

We're not interested in supporting templating systems. But with #337 you can add it yourself.