* provides a "close plugin library" button
* starting from #1718 by @inmysocks
* possibly fixes all of #1718, #1597, and #2067
* corrected code comment
* add back title
No idea why I overlooked this beforehand.
Next time I will not suggest such changes that have little to do with
the PR, but rather just comment the code.
* ah, sorry, "fixed" wrong spot
now
```
<$action-sendmessage $message="tm-load-plugin-from-library"
url={{!!url}} title={{$(assetInfo)$!!original-title}}/>
```
...should be back at the right spot.
* mhhh... still fixing the mess
load, unload, puh... let's see if I got it now
* added unloadIFrame and minor syntax fixes
88a65f038e