Update cwltool and galaxy-lib dependencies for Python 3.7

Fix galaxyproject#863 .

Need releases which include respectively:
common-workflow-language/cwltool#831
galaxyproject/galaxy-lib#129

Author: nsoranzo

requirements.txt

@@ -14,6 +14,6 @@ virtualenv
 lxml
 gxformat2>=0.2.0
 ephemeris>=0.8
-galaxy-lib>=18.5.13
+galaxy-lib>=18.5.14
 html5lib>=0.9999999,!=0.99999999,!=0.999999999,!=1.0b10,!=1.0b09
-cwltool==1.0.20180508202931
+cwltool==1.0.20180820141117