Move last_updated(), date_created() and epoch() to methods.common.
Properly test that DATE_CREATED is in the document.
Default DATE_CREATED for single document GET.
Default DATE_CREATED/LAST_UPDATED on edit methods.

These fields need a default value if missing, so ETag will be computed
on the same representation of GET.
Test edit action on document with missing 'created' field.
Changelog update.
Merge branch 'issue123' into develop. Closes #123.
Typographical mistakes.
Francisco Corrales Morales
Merge branch 'franciscocorrales-patch-1' into develop
'default' added to docs.
Quickstart typos and updates.
Gittip widget.
Gittip widget also on the frontpage.
Changelog redesign: New Features, Enhancements and Fixes.
Merge branch 'develop'
v0.1 release date.
Version bumped to v0.1, ready for release.
Shorter project description.
Development Status: 4 - Beta.