Update WP Read-only (fixes broken image editor)

Fixes an issue where, after editing and saving an image using the WordPress image editor, the edited file was not made available on S3. 

Also fixes an issue where temporary directories weren't being removed after assets are transferred to S3.
client_max_body_size should == upload_max_filesize

The default nginx value for client_max_body_size is 1mb. But the php.ini value for upload_max_filesize is 2mb. These should be the same.
Merge pull request #19 from peterhartree/master

Update WP Read-Only (fixes broken image editor)