api: add support for timestamp in _list_resources()

Change-Id: I683bcbc2072b782eb94739aaa99e151ee9d0df3e
Signed-off-by: Julien Danjou <julien@danjou.info>

Conflicts:

	tests/api/v1/test_list_resources.py
Merge branch 'deploy' into stable/folsom-att-working-timestamp-filter