Merge remote-tracking branch 'angelina/patch-1'

Patch by AngelinaBelle: https://github.com/doherty/WP-vanilla-pdf-embed/pull/4

Fixes several corner cases.

git-svn-id: https://plugins.svn.wordpress.org/vanilla-pdf-embed/trunk@907231 b8457f37-d9ea-0310-8a92-e5e31aec5664
Tested with 3.9.0

git-svn-id: https://plugins.svn.wordpress.org/vanilla-pdf-embed/trunk@907232 b8457f37-d9ea-0310-8a92-e5e31aec5664