added lxml/libxml2 versions to 'scrapy version' output

scrapy/commands/version.py

@@ -21,7 +21,16 @@ class Command(ScrapyCommand):
 
     def run(self, args, opts):
         if opts.verbose:
+            try:
+                import lxml.etree2
+            except ImportError:
+                lxml_version = libxml2_version = "(lxml not available)"
+            else:
+                lxml_version = ".".join(map(str, lxml.etree.LXML_VERSION))
+                libxml2_version = ".".join(map(str, lxml.etree.LIBXML_VERSION))
             print "Scrapy  : %s" % scrapy.__version__
+            print "lxml    : %s" % lxml_version
+            print "libxml2 : %s" % libxml2_version
             print "Twisted : %s" % twisted.version.short()
             print "Python  : %s" % sys.version.replace("\n", "- ")
             print "Platform: %s" % platform.platform()