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.

added 10 commits

• 21507c5d...f5f294fb - 3 commits from branch master
• 3307ab0e - port python2 print statements in various scripts/modules
• 9c3a3c29 - gstlal_inspiral_calc_snr: define missing_required_options earlier to avoid not defined issues
• 9b71d01b - gstlal_inspiral, gstlal_ll_inspiral_plot_sensitivity: fix StringIO calls
• 3294a38e - address tab/space mixing issues
• 9741fbe4 - chirptime.py: convert windows-formatted file
• fab532a7 - fix undefined variable errors
• 432a832c - segments.py: fix type annotation return in split_srgments_by_lock, remove...

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merged