If you press the Ctrl key after the drag starts, the green "+" next to the cursor will change to a small "link" icon. This changes the behavior so that the path is added instead of the files contents.

This is standard Mac Drag & Drop behavior.

You can find instructions for installing the Swift syntax definition in the iOS apps here:

http://feedback.textasticapp.com/topic/454769-swif...

I plan to add it in the next update, but for now you can install it manually.

Hello,

if you are using the full version from the Mac App Store (not the trial version), you should see an iCloud tab in the open dialog (File -> Open) that contains all your iCloud documents. 

Currently not. You can see the complete file name in the text field of the rename dialog: http://www.textasticapp.com/v5/manual/lessons/How_can_I_move__copy_and_rename_files_and_folders.html#step_4

Not at the moment, sorry.

You can add custom syntax definitions to Textastic by using TextMate bundles. See
http://www.textasticapp.com/v5/manual/lessons/How_...

A quick search for "twig tmbundle" in Google brought up this TextMate bundle which should work:
https://github.com/Anomareh/PHP-Twig.tmbundle

You can find a list of hardware keyboard shortcuts at http://www.textasticapp.com/v5/manual/lessons/Whic...

I'm not aware of a shortcut to delete the current line.

I'll see what I can do.

Thanks for letting me know!