mfparbc should use a ULSTRD equivalent reader

[christianlangevin]

In this part of the code:

flopy/flopy/modflow/mfparbc.py

Line 179 in ff43c7c

for nc in range(nclu):

MODFLOW uses the ULSTRD reader to read in the list. ULSTRD allows for EXTERNAL, OPEN/CLOSE and SFAC to be specified, which directs the read to an external file, to an open/close file, and optionally multiplies a column by SFAC.

So this part of mfparbc should use some sort of ULSTRD equivalent.

The following is a valid GHB input file, which shows the use of EXTERNAL following the first parameter definition. At the moment, flopy will try to read external as a valid ghb record, when it should be reading from unit 50.

PARAMETER          4     40275
       711        40   NOPRINT
MARGINAL         GHB       1.0       585
EXTERNAL          50
...

[christianlangevin]

By the way, this also appears to be an issue here:

flopy/flopy/pakbase.py

Lines 830 to 838 in ff43c7c

	for ibnd in range(itmp):
	line = f.readline()
	if "open/close" in line.lower():
	binary = False
	if '(binary)' in line.lower():
	binary = True
	# need to strip out existing path seps and
	# replace current-system path seps
	raw = line.strip().split()

where EXTERNAL and SFAC also do not appear to be supported. How can this be?!