Fixes in the structDiffMd.py file

[CyrilleB79]

Various fixes following issues found in the first generated structure difference report for the User Guide:

• Added one more space to vertically align the English and translated lines for better comparison in the output file.
• RE_LINE regexp is less restrictive regarding the order of the content of the "title" tag (e.g. Russian User Guide)
• RE_LINE regexp is less restrictive for the "(settingsSection" tag's content to allow dash character (e.g. German User Guide)
• Explicitly specify the output file encoding to UTF-8 to be able to run the script under Windows (e.g. for Russian)

[CyrilleB79]

Cc @michaelDCurran