test current line counter and start new page if needed.
increment counter before returning.
optionally print secondary header if new page.
lmax - maximum lines allowed on this page
linc - number of lines about to be printed
itf  - non-zero to select optional secondary header

save header string for subsequent calls
set up extra output unit (or lack thereof)
lhed - text string for header, or lhed(1)=-1 for setting up iout2
n    - iabs(n)=length of lhed in words, + if top line, - if 2nd line
if lhed(1)=-1, then n is second output unit

set up page top
pname  - name of integrated object (r*8)
jd1,2  - range of integration
fmth   - array containing format(if any) for optional 2nd line
(MUST be either a binary 0 or a 136-character string)

print new page top + maybe second line
ioutt  - output print unit number
mpage  - next available page number on ioutt
jdz    - optional extra line control, if .gt.0 print extra line
(format saved on latest call to NEWPGS)