Fixes minor threading issue

Fixes #64, thanks @jwelton!

Swift 4

2.5.0

Bumps up podspec to 2.5.0

Adds ability to display PDF starting from a specified page index

2.4.0

Bumps up podspec version

Adds Xcode 8.3 support

• Pre-compiled binary built on Xcode 8.3

Adds ability to display PDF from Data or a remote URL

2.3.0

Bumps up podspec version

Fixes rotation bug

• Fixes #41: Properly rotates PDF according to its rotation angle

Bug Fixes

• Fixes #44
• Fixes #45, thanks @bilallourd

Adds several new customization endpoints

• isThumbnailsEnabled whether to load and display the thumbnail bar at the bottom #38
• scrollDirection scroll direction of the PDF (vertical or horizontal) #40
• collectionView is now public #39

Fixes thumbnail caching bug

Includes fixes for #35 and #36

Fixes performance issues when opening up large documents

• No longer waits for all the thumbnail images for all the pages to render when loading the first page; loads thumbnail images in the background, and then when they are eventually all loaded, updates the thumbnails.
• Adds a very large pdf for testing performance issues