Fix printing behaviour in Chrome

Two major issues:
1. Border/shadow around every page. Removed by adding "border:none".
2. Added "overflow:visible" (overrides "overflow:auto") in #viewContainer.
   This solves two problems:
   - It prevents scrollbars from appearing.
   - Every "page" is automatically resized to fit on a printed page,
     just like the Firefox.
To see what's wrong, here's a picture of how PDF.js rendered the pdf in
 Chrome (using "Print to PDF" feature of Chrome):
 https://robwu.nl/pdfjs/pdfjs-print-with-chromium-28.pdf

Successfully tested with Chrome 28 and Firefox 22.

Solves #3445

web/viewer.css

@@ -1332,6 +1332,9 @@ canvas {
   #sidebarContainer, .toolbar, #loadingBox, #errorWrapper, .textLayer {
     display: none;
   }
+  #viewerContainer {
+    overflow: visible;
+  }
 
   #mainContainer, #viewerContainer, .page, .page canvas {
     position: static;
@@ -1342,6 +1345,7 @@ canvas {
   .page {
     float: left;
     display: none;
+    border: none;
     box-shadow: none;
   }