Bump schema-salad version for validation performance fixes. (#200)

Author: tetron

setup.py

@@ -46,7 +46,7 @@
           'rdflib >= 4.1.0',
           'rdflib-jsonld >= 0.3.0',
           'shellescape',
-          'schema-salad >= 1.18',
+          'schema-salad >= 1.18.20160930145650',
           'typing >= 3.5.2',
           'cwltest >= 1.0.20160907111242'],
       test_suite='tests',