Do not emit a warning to use capital letters in text fields

[magsilva]

Currently, JabRef emits a warning when using capital letters on some textual fields, such as the title. This is due to BibTeX's handling of capital letters within words that do not start a sentence, lowering their case by default. Indeed, if the word represents a proper name or an acronym, emitting a warning for that is the right thing to do. However, in most cases, this is harmless.

My suggestion is to disable this warning or just emit it when the capital letters are used for acronyms.