* lib/model: Remove bogus fields from connections API endpoint.
Switch the returned data type for the /rest/system/connections element
"total" to use only the Statistics struct. The other fields of the
ConnectionInfo struct are not populated and misleading.
* Lowercase JSON field names.
* lib/model: Get rid of ConnectionInfo.MarshalJSON().
It was missing the StartedAt field from the embedded Statistics
struct. Just lowercasing the JSON attribute names can be done just as
easily with annotations.
* lib/model: Remove bogus startedAt field from totals.
Instead of using the Statistics type with one field empty, just switch
to a free-form map with the three needed fields.