Fixes and updates for media uploads in the new editor

This PR fixes https://github.com/wordpress-mobile/WordPress-iOS-Editor/issues/344 and contains an updated editor pod which fixes an issue with remote URLs on images not being updated.

/cc @diegoreymendez 
@bummytime - I'm also getting a never ending upload spin wheel. This happens on private blogs it seems - probably because the remote image download fails. One thing we can do is stop the speen wheel even if the remote image download fails.