Your comments

You need to get the files into Textastic first. There are several ways how you can do this:
  • Download it on your computer and copy it to your Dropbox or an FTP server and download it using Textastic
  • You could also send it as an email attachment to yourself and use "Open In..." in Mail
  • Probably the easiest way: in Safari on the iPad, replace "http://" in the download url with "textastic://" and it will download the zip file in Textastic. So for the bundle you mentioned, use this url: textastic://bitbucket.org/jeremybise/expressionengine-2-bundle/downloads/expressionengine-2-bundle-tip.zip

When you have the zip file in Textastic, and unzip the folder by tapping on it and move it into the #Textastic folder as shown in the manual.

Actually, the problem is the following:
Textastic uses the Core Text API of iOS to draw the syntax highlighted code. The longer the text that needs to be drawn, the longer it takes. So, Textastic divides the file into lines and does the layout and drawing of each line separately as soon as it comes into view. Lines that are not visible are not drawn.
In the case of a minified JQuery file, the file is one really long line. Core Text takes a long time to layout and draw this syntax highlighted line. It even takes a long time when there is no line break involved. It would only be faster if the whole line was just one font with one color but even then it wouldn't be instantaneous.
You can see the same problem in other editors. Even the Notes app has similar problems with very long lines. TextMate on the Mac is also very slow with such a file - but it isn't as noticable because desktop processors are much more powerful. So I don't think this can be solved.
To solve the problem that Textastic isn't responding anymore:
Textastic should recognize after two tries that it couldn't open the file when it was launched last time and not open it again. Just try to launch the app until the file isn't opened anymore.
I do plan to offer the iPhone version as a separate app. There are a few problems I'll need to solve, but the editor is already working well. It should be available in a few weeks.
Currently not. I'll consider adding import functionality in a future update.
See also http://webdesign.about.com/od/beginningtutorials/a/aa040502a.htm

  • links in the same directory as the page have no path information listed: filename
  • sub-directories are listed without any preceding slashes: directory/filename
  • links up one directory are listed as: ../filename

You can do that: just write images/image.png - you need to leave out the first slash. The slash would tell it to look at the root directory - just like on a real web server.
Please try to use the T-SQL TextMate bundle from https://github.com/adamv/tsql.tmbundle

Have a look at http://www.textasticapp.com/v4/manual/lessons/How_can_I_add_my_own_syntax_definitions__themes_and_templates.html to see how you can install it in Textastic.