Squashing commits for the close findbar feature
Update web/viewer.js

The variable isLocalStorageEnabled is now unused in Firefox and B2G.
Merge pull request #2703 from timvandermeij/close-findbar-without-focus

Close findbar also when focus is away from it
add imageLayer

add optional imageLayer object to access images and there
position and size as they are rendered on the canvas.
Adds zoom buttons ids (follow up on #2707)
Merge pull request #2708 from marco-c/patch-1

Update web/viewer.js
Merge pull request #2693 from bit/master

expose information about images on canvas