The default whitespace normalization, used for non-raw versions of the

gettext functions, was pretty basic. It just collapsed down all

whitespace and trimmed the resulting string.
This works great for simple strings, but we've run into cases where we

have paragraphs of content we want to work with, and that wasn't at all

clean. The new support for plugins like dedent helps, but preserves

newlines, and that's exactly what we're trying to avoid.
This change improves the whitespace normalization to preserve

paragraphs. Any two paragraphs must be separated by one or more blank

lines. The whitespace normalization will be performed within each

paragraph. The final resulting string will normalize the blank lines

between each paragraph and trim the results.

Unit tests passed.
Manually tested with some code in Review Board.
Verified the rendered information in the README.