ENH/CLN: Give AssertionErrors and nose.SkipTest raises a message
ER: give a better error message for hashing indices
Merge pull request #3730 from cpcloud/parse-exceptions

ENH/CLN: give all AssertionErrors and nose.SkipTest raises an informative message
Merge pull request #5019 from cpcloud/raise-on-index-hash

ER: give a better error message for hashing indices