[Documentation] Could the main README show which fox version is supported?

[rubyFeedback]

Hey lars,

Fox toolkit still makes releases:

http://www.fox-toolkit.org/

Current dev version is 1.7.85.

I assume fxruby supports only the stable version:

1.6.58 # right now

Could the main README clarify this though? In particular if the dev version may be supportable or so. This may help folks try out changes before they eventually come into a new stable release - in a few decades or so. :D