Your comments

It looks interesting, but judging by the Readme, it probably won't support many real life configurations - i.e. modern authentication methods. Also, the last library change was a year ago.
It's great to hear that it's working for you now.
Is your key file protected by a pass phrase? You need to enter the pass phrase in the password field below the user name. 
Es gibt eine alte Version des Handbuchs auf deutsch unter http://www.textasticapp.com/de/manual/

Allerdings wird dies nicht weiter gepflegt und enthält weniger Einträge.
Sounds interesting. I'll have a look at Heroku.
If you upload a folder, it will upload all files and overwrite the remote ones.

I'm currently not working on syncing. As you say it's hard and it's easy to make mistakes which would result in data loss. Maybe in a future update.
Currently, there is only code completion for built-in PHP functions (like addslashes() or mysql_connect()). There is currently no code completion for statements like if, for, foreach etc. - I plan to extend PHP code completion in the future.
CodeIgniter seems to be written in PHP, so it can't be run on iOS without a full PHP environment.