Display a FITS header (or other string array)
On a GUI terminal, the string array is displayed using XDISPSTR.
If printing at a non-GUI terminal, the string array is printed 1 line
at a time, to make sure that each element of the string array is
displayed on a separate line.
HPRINT, h, [ firstline ]
H - FITS header (or any other string array).
FIRSTLINE - scalar integer specifying the first line to begin
displaying. The default is FIRSTLINE = 1, i.e. display
all the lines. If Firstline is negative, then the first
line to be printed is counted backward from the last line.
When displaying at the terminal, HPRINT has the following differences
from the intrinsic PRINT procedure
(1) Arrays are printed one line at a time to avoid a space between 80
(2) Lines are trimmed with STRTRIM before being printed to speed up
(3) The /more option is used for output.
Read the header from a FITS file named 'test.fits' and display it at the
terminal beginning with line 50
IDL> h = headfits( 'test.fits') ;Read FITS header
IDL> hprint, h, 50 ;Display starting at line 50
To print the last 25 lines of the header
IDL> hprint, h, -25
Written W. Landsman July, 1990
Added test for user quit July, 1991
Added optional FIRSTLINE parameter November, 1992
Modified for when STDOUT is not a TTY W. Landsman September 1995
Converted to IDL V5.0 W. Landsman September 1997
Fixed printing in IDLDE, C. Gehman August, 1998
Skip PRINTF if IDL in demo mode W. Landsman October 2004
Fixed bug on non-terminals, William Thompson, 18-Oct-2004
Assume since V5.4 Use BREAK instead of GOTO W. Landsman Apr 2006
Call XDISPSTR on a GUI terminal W. Landsman Jun 2006