Added new method, view(), for use when debugging

[BritishWerewolf]

I have added in a new method that can be called in the same way that stream is in order to print raw HTML to the browser.
This is useful for debugging the HTML to view what the code will look like - roughly.

Also, I have modified the comments on the config array so that they reflect the wording from the Mpdf documentation.

[verbeeksteven]

@niklasravnsborg - Need this for testing, could we get it merged?

[bomshteyn]

This seems like a very good idea, thanks @JustCarty.

@niklasravnsborg is this being merged in?

[niklasravnsborg]

Hey guys! I hear you on this. I cannot merge at the moment. Maybe @erfansahaf can look at it? Thanks for your patience. :) Have a good weekend.

[erfansahaf]

@niklasravnsborg I'm busy for now, but I'll review all merge requests as soon as I can.