Implement simple disconnection mechanism (wipe the access token).

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@864353 b8457f37-d9ea-0310-8a92-e5e31aec5664
Save `reblog_key` on import via sync. Version bump to 0.7.2.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@864354 b8457f37-d9ea-0310-8a92-e5e31aec5664
Fix formatting in readme file.

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@864365 b8457f37-d9ea-0310-8a92-e5e31aec5664
Um. Formatting fix?

git-svn-id: https://plugins.svn.wordpress.org/tumblr-crosspostr/trunk@864368 b8457f37-d9ea-0310-8a92-e5e31aec5664