Followup fix for entering/exiting Presentation mode

Even after PR 5359, switching to/from Presentation mode is still sluggish and I'm still seeing `too much recursion` printed in the console.
I've managed to track down the issue to line https://github.com/mozilla/pdf.js/blob/master/web/page_view.js#L371. It appears that for this particular case, we actually *need* to set `noScroll = true` when calling the `_setScale` function. (Note that it only applies to *this* line, and not to Presentation mode in general.)
Given the amount of refactoring done to the viewer, I'm not sure what the best way to fix this would be. However I'm submitting this patch as an easy workaround for now, but we should probably refactor this to avoid calling a "private" method directly.
Merge pull request #5360 from Snuffleupagus/pr-5359-followup

Followup fix for entering/exiting Presentation mode
Moves scrollPageIntoView to the PDFViewer.
Adds css import preprocessing
Merge pull request #5361 from yurydelendik/movescrollinto

Moves scrollPageIntoView to the PDFViewer.
Move text_layer_builder and pdf_viewer styles out
Merge pull request #5362 from yurydelendik/css-import

Use CSS import to separate pdfviewer styles
Rename FontFace to FontFaceObject

This name clashes with the FontFace constructor from the Font Loading CSS module:
http://dev.w3.org/csswg/css-font-loading/#font-face-constructor
Packages PDFViewer as a UI component.
Introduces 'pagesinit' event.
Merge pull request #5363 from yurydelendik/pdfviewecomponent

Packages PDFViewer as a UI component.
Use Font Loading API if available

http://dev.w3.org/csswg/css-font-loading/
Fixes enabling pdfBug
Merge pull request #5367 from yurydelendik/fixpdfbug

Fixes enabling pdfBug
Fixes examples comments.
Merge pull request #5366 from Rob--W/use-font-loader-api

Use font loader api
Add a page loading indicator to the page number input
Add updated loading-small.png (and corresponding Retina) asset
Fixes printing regression a10fde1
Merge pull request #5368 from yurydelendik/fixprintcss

Fixes printing regression a10fde1