Multiple line text blocks in GUI

```
What steps will reproduce the problem?
1. Open Gui
2. Select "Ab" text block adding feature, then cick on canvas for
location to add text block
3. "Add a new text" window pops up, but only allows adding a single
line of text (i.e., multiple-line text blocks not supported)

What is the expected output? What do you see instead?

Would like to add multi-line and even multi-paragraph text
blocks, but only a single line is allowed. Workaround is to
add multiple single-line text blocks, but that can become a
minor annoyance.

What version of the product are you using? On what operating system?

Latest core svn bits as of 05/30/2013, on ubuntu 12.04.

Please provide any additional information below.
```

Original issue reported on code.google.com by `fltemp...@gmail.com` on 31 May 2013 at 5:40