Setting EDITOR environment variable?

```
What steps will reproduce the problem?
1. Load .pdf file: pdf = PDF.read 'sample.pdf'
2. Try to edit: pdf.pages[2].edit
3. Error occured:
>>> pdf.pages[2].edit
NoMethodError: undefined method `edit' for nil:NilClass
from (irb):2
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/origami-1.2.3/bin/pdfsh:12:in `'
from C:/Ruby192/bin/pdfsh:19:in `load'
from C:/Ruby192/bin/pdfsh:19:in `'

What is the expected output? What do you see instead?
Possibility to edit page raw contents, but error occured instead.

What version of the product are you using? On what operating system?
Ruby 1.9.2-p290, Origami 1.2.3, Windows 7 Enterprise x64

Please provide any additional information below.
In GettingStarted guide said that "the EDITOR environment variable may need to
be set up", but I don't know how to do that. I'm new to Ruby...
I tried to read all ReadMe-like files in ORIGAMI folder, but there is no
information about setting EDITOR environment variable. Internet searh also
doesn't help, Origami's PDF "origami-cheatsheet-1.0.0-beta2.pdf" too... I
assuming that this feature is un-documented. :(
Can I ask for help here, please?

Thanks in advance.

Kind regards,
Stole
```

Original issue reported on code.google.com by `condor...@gmail.com` on 26 Oct 2011 at 12:30