Now extracts text from WordPerfect documents (new WordPerfectParser
class).
New transformer "ReduceConsecutivesTransformer" to reduce consecutive
instances of the same string to only one instance.
New transformer "ReplaceTransformer" to perform search and replace on
document content using regular expression.
New filter "EmptyMetadataFilter" to exclude/include documents with no
data for one or more specified metadata properties.
Fixed NPE in AbstractTextRestrictiveHandler when no content-type is
found when used before parsing.