Fix bug in Quote posts that failed to capture multiple line quotes.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@854328 b8457f37-d9ea-0310-8a92-e5e31aec5664
Version bump to 0.5.1.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@854329 b8457f37-d9ea-0310-8a92-e5e31aec5664