Add Support for Capitalization in Titles and Captions

[patrikreiske]

Often times, the style of documents requires capitalization of words or phrases in titles and captions. Examples would be

Normal Text	Titles and Captions
deep learning	Deep Learning
hidden Markov model	Hidden Markov Model
sequence to sequence	Sequence to Sequence

This, however, is not (fully) supported by the package: As of now, only the first letter of the first word in a phrase can be capitalized but not every word's first letter or some words' first letters. Therefore, I suggest

• adding a package flag for enabling automatic capitalization of any word in an acronym phrase when in a title or caption environment,
• adding a flag to all existing commands entering the long form of acronyms inside text or adding likewise new commands to manually force the use of the capitalized form, and
• adding an optional field to the \acro command to specify notations where not all words in the phrase (like for "sequence to sequence" / "Sequence to Sequence") are capitalized.

Thanks.

Edit: Spelling

[johanna4711]

+1 please.

[oetiker]

Sounds like a good plan!