Fix man page (#403)

[thiagowfx]

• Updates man page with newly added flags since 2015. Man page had been last updated only in 2015.
• Fix formatting of flags in man page. Instead of joining lines, now each flag is correctly displayed in its own line, making it easier to read.
• Fix man page generation script, which was broken and still referencing the old usageStrings.py (correct filename is usage_strings.py).

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[KapJI]

Please format your code using black.

[thiagowfx]

Done.

[KapJI]

Thanks!