Use ripunzip for unzipping whole archives if available (fixes #16)

Note that ripunzip only for unzipping and listing complete archives.

Resolves #16

Change-Id: I12d120184f7194ca32bcd1ea4e3a76acd5f47e28
diff --git a/script/korapxml2krill b/script/korapxml2krill
index a40d75a..c522b32 100755
--- a/script/korapxml2krill
+++ b/script/korapxml2krill
@@ -1504,6 +1504,12 @@
 By providing the number of parallel jobs using C<--jobs>, the execution can be tailored to specific
 hardware environments.
 
+=item Install ripunzip
+
+For full extraction of data, L<ripunzip|https://github.com/google/ripunzip> can be
+used for improved performance.
+
+
 =head1 ANNOTATION SUPPORT
 
 L<KorAP::XML::Krill> has built-in importer for some annotation foundries and layers