Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20111001 Thunderbird/7.0.1
If I have a large begin_src block it can make reading the surrounding
text difficult, as the reader has to keep paging up and down. Ideally it
would be possible to fold src blocks, but I can see that would be
inconsistent with org's structure. I could put the block in a draw, but
was interested in what others do.