Replacement for the now retired "fixed-width font" Gmail labs feature

http://groups.google.com/group/gmail-labs-help-fixed-width-font/

Whereas the original labs feature made the fixed-width rendering an optional extra on a per-message basis, this will simply make the message body of plaintext messages to *always* display in your browser's monospace font.

Additionally, it will also do this to the plaintext editor textarea (though I still prefer the "it's all text" firefox plugin so I can use vim ;-)).

Based on the the greasemonkey user-script: http://userscripts.org/scripts/show/17869 by http://userscripts.org/users/jparise whose CSS i've extracted, and expanded to also make it work on the plaintext editor.