[R-390] Added front pictures to our website's 'variations' page

[Larry H]

Hi all,  I added some front panel pictures to our website's 'variations'
page for most of the important receivers listed there.  I did this for
the R-389,
R-390, R-390A, R-391 and R-392 by adding a link to Luca Fusari's website.
I found a good picture of the R-648, so put it on our website with a
link to it in the R-648 description.

Here's a direct link to the 'variations' page: The R-390A Frequently Asked
Questions Page <https://www.r-390a.net/faq-var.htm>.

If you would like a picture of the others added, please send it to me (be
sure it's not copyright protected).

Regards, Larry