Changes to EvDocumentIface committed

[Kristian Høgsberg <krh redhat com>]

Hi,

I've committed a change to the document interface that removes some of 
the state in the document.  Specifically, we no longer have a current 
page or a current scale as part of the document state.  Instead, all 
operations on the document must pass in the desired page and scale.  The 
reason for doing this change is that I was hitting some race conditions 
with the search going on in main thread idle callbacks while the 
rendering thread was changing the current document page.

As a consequence of this change all coordinate and dimension arguments 
are now unscaled document units instead of pixels, and I've changed the 
argument types from ints to doubles.

cheers,
Kristian