API: very first commit to test the git-flow
Porting Biostar1 API to Biostar2

Create a util.dates module for date conversions.
Create a util.stats module for stats about the website.
/api/stats still WIP: file caching and conversion of the logic from days-ago to days-from-zero-day still missing.
Add more fields to /api/post
Add /api/vote/<id>
Add cached stats files for /api/stats/<days>
Use HTTP status 404 when a resource is not found
Convert /api/stats/ to a day-ago logic to a date and days-after-day-0 logic
Create package biostar.server.tests

Move server/test.py inside this package and rename it to test_functional.py.
Add test_api.py meant to test the api.
Fix typo (ZERO_DAY to DAY_ZERO)
Refactoring api module: move code from util package to api module
Add a few unit tests
Unit tests for /api/traffic
Unit tests for /api/user
Fix typo (a white space in 2 strings)
Unit tests for /api/vote
Fix issue w/ SimpleTestCase

For all tests interacting w/ the DB we must use TestCase or TransactionTestCase (not SimpleTestCase).
Unit tests for /api/post
Fix: do not create stats files in debug mode
Unit tests for /api/stats
Remove sharing flatpage, add api