[trunk] Style Hrd/Ftr Nums "show first" not checked, 1st page > 1: 1st page number still shown

Tthis is a port to trunk of the patch for issue #15147: [branch 1.2] Style Page Nums "show first" not checked, 1st page > 1: 1st page number still shown (branch 1.2). The same details apply to it too.

I have corrected both the header and the footer part. As trunk distiguish between even and odd header/footer, I have corrected the concept of "page numbered 1" into "first page", but I have left the current logic for even/odd. To summarize what chanced and what didn't:

case a) first page numbered 1:
before: page "first" and "odd"
now: page "first" and "odd"

case b) first page numbered 2:
before: page "non-first" and "even"
now: page "first" and "even"

case c) first page numbered 3:
before: page "non-first" and "odd"
now: page "first" and "odd"

(and so on)

This is what I would expect and I believe it to be the most usual meaning of the terms.

Note: there is bug in the "Layout | Page settings" dlg box, which messes with the first page number actually entered. More details in a proper issue, as soon as I understand them.

Thanks,

M.