Removing the transient caching.

While this was a good idea in theory, it caused too many problems, especially for people who use Instagram a lot and had many likes/comments.
Using <?php instead of <? is better.
Only save the picture if we don't have it already.

Which should stop the duplicate picture bug that some users have and that I can't reproduce on my end.
Bumped the version number.
Merge branch 'release/0.4'