Assorted fixes

While doing some cleanup with the unused imports, I also ran into various issues throughout that this MR fixes:

• Port various python2 print statements throughout
• gstlal_inspiral_calc_snr: Move missing_required_options upstream to avoid running into issues where it hasn't been defined yet
• Fix a couple of StringIO() calls that were not correct. (if StringIO is imported from io, it should be StringIO(), not StringIO.StringIO().
• chirptime.py file had Windows formatting, so that was converted via dos2unix
• Fix a couple of undefined variable problems due to typos.
• Remove unused variable in segments.py
• Fix wrong return type annotation in segments.py.

gstlal-inspiral/bin/gstlal_inspiral_calc_snr

@@ -275,6 +275,8 @@ def parse_command_line():
 	# Do general program options checking
 	#
 
+	missing_required_options = []
+
 	if options.outdir is None:
 		missing_required_options.append("--outdir")
 
@@ -315,7 +317,6 @@ def parse_command_line():
 	assert options.row_counts >= 1, "Number of rows to be outputted must be larger than or equals to 1." 
 	# Use LLOID method
 	if options.mode == 0:
-		missing_required_options = []
 		# Checking required options
 		if options.svd_bank is None:
 			missing_required_options.append("--svd-bank")
@@ -339,7 +340,6 @@ def parse_command_line():
 
 	# Use Finite Impulse Response
 	elif options.mode == 1:
-		missing_required_options = []
 		# Checking required options
 		if options.bank is None:
 			missing_required_options.append("--bank")