Support for maintaining original case

[esilgard]

• commit 1: test coverage for maintaining original character casing
• commit 2: optional cmd line arg for maintaining case in file input (defaults to original, lower cased segment output)
• commit 3: maintaining case logic -- loop through segmented output -- refer back to original input text by character offset -- track white space in original text and increment offset accordingly

[Kristinita]

@grantjenks , please, review this pull request when you will have a time.

Thanks.