It could also be an encoding problem. I'll try it tomorrow.

Maybe you entered symbols that don't exist in the font files on the iPad.

I did enter them using the Emoji keyboard on the iPad. You can add this keyboard in Settings on your device.

Yes, implementing a "Show invisibles" feature instead of just "Show tabs" would definitely be very useful!

At the moment, Textastic can show tab characters as gray triangles.

I have just tried it and it works for me with all fonts. See the attached screenshot.

Just a quick status update:

I am currently working on Git support, but it will take quite some time before it is going to be finished. I have to write my own Git library from scratch, because there is no Git library written in C, C++ or Objective-C that supports network functions like push and pull over SSH as it is needed for GitHub. All existing solutions can only manipulate local repositories or only support a subset of network protocols. 

Also, most libraries are licensed under the GPL which can't be used in an iOS app.

libgit2 is written in C and licensed under the GPL with a linking exception. So I could in theory use it, but it lacks network protocol support. I'm not good enough in writing plain old cross-platform C code, so I can't really add those features myself. Also, I don't like the license.

Git.framework, written in Objective-C, can only manipulate local libraries and doesn't seem to be under active development.

JGit, which is used by Eclipse, is full-featured and uses the new-style BSD license, so it would indeed be perfect. But, it's written in Java, which I can't use on the iPad.

So I came to the conclusion that I'm going to write my own Git library using Objective-C. This has the added benefit of giving me a full understanding of Git internals.

Currently, it's hard for me to estimate if and when I will succeed with this project, but I'm trying my best.

Sorry, but Apple doesn't allow compilers in third-party apps. Instead, you can upload such files to a server and run it there - for example using an SSH app like iSSH or Prompt.

Did you see that you can tap on the current file name to get a list of recently opened files?

See http://www.textasticapp.com/v4/manual/lessons/How_can_I_show_a_list_of_recently_opened_files_How_can_I_close_the_current_file.html