Small changes in obfuscation_utils and lang_utils

[netsettler]

• Add is_obfuscated.
• Add obfuscated= argument to obfuscate and obfuscate_dict.
• Add "from" and "between" to list of prepositions that the pluralizer understands.

[coveralls]

Pull Request Test Coverage Report for Build 2887400371

• 14 of 14 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.02%) to 70.619%

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Totals
Change from base Build 2874939441:	0.02%
Covered Lines:	5295
Relevant Lines:	7498

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💛 - Coveralls