Adding back button to the metadata summary page
add head request to base handler
fix typo
proper codes for 404 page
fix test for new 404 error
Merge pull request #495 from squirrelo/add-head-response

Add head request to base handler
Make first_contact use DB time instead of python
flake8 fixes
Use os.path.join instead of concatenation
Permit NOT NULL columns that have a default val
Fix tests for new DB timestamp

Fixes #343
Merge pull request #474 from josenavas/metaback

Adding back button to the metadata summary page
Merge pull request #511 from adamrp/study_create_db_time_issue-343

Study create db time issue 343