Api handler refactoring using the wrap and response func/type, fixed small issue in influxdb 0.9 response handling

Update latest.json

fixing #2021

This tiny commit fixes a routing problem for proxy requests. The
router was expecting a url path behind the proxy id, if none was
given (read: the service proxied was at the root of a host) then
the router would return a 404. With this patch it now propperly
uses ProxyDataSourceRequest.

Worked on user administration page, a grafana server admin can now add and edit organization roles for any user, #2014

no unbound recursion in publish()

unbound recursion approach can blow up call stack,
and - I think - allocate memory unboundedly as well.

We can simply loop until err != nil

I didn't actually test this live, though tests succeed

Lots of progress on InfluxDB Query Editor, show tag keys, values and measurement dropdowns now take into account already selected tags or measurements, so you can start with tag keys and the select measurement, #1525

fix mac.md for incorrect href

Minor work on InfluxDB 0.9 query editor, #1525, hit a roadblock with the new InfluxDB query language, does not support tag and tag values discovery queries with filters, not sure if I need to move to SHOW SERIES style queries

Addresses #1853, redact session provider secrets

In cases where a database is used for session storage, redact the
session_provider config value. I assumed "@" as the marker for a
database vs file/memory.

Backend configuration: When unknown key was detected the log error was not visible in log file due to logging was initialized after user config file is loaded, logging is now initialized twice, once based on defaults and command line arguments, then then again after user config file, Fixes #1992

Fix minor grammar issue in docs index page