TST: let tox run more tests
Added link to epoch handling in read_csv
Added correct link to cookbook for CSV read with epoch timestamps
Merge pull request #3771 from nipunreddevil/cookbook-epoch-handling

Cookbook epoch handling
BUG: (GH3481) revised, fix concat to allow a passed generator as the single arg

     (also list/tuple/dict)
Merge pull request #3770 from cpcloud/tox-let-more-tests-run

TST: let tox run more tests