Filtered continuous changes feeds report progress when filters fail
At times some filters are very strict and thousands of docs might
pass thru without success. If a timeout occurs the changes feed could
be requested again starting from the same sequence. This patch fixes this
by reporting a seq back to the controller even when the filter fails. The tricky
part is that this subverts the normal rexi mechanism of using inactivity
to determine a timeout has occured for purposes of a heartbeat. To solve this
an additional "time since last real change" is tracked in the controller.

BugzID: 17709
Send a no_pass message to fabric controller
When a filter function fails for a given document send
the sequence back to the controller. This enables long
running changes feeds that may timeout to return the last
sequence processed to the caller

BugzID: 17709
Establish a cap for reporting docs that fail filter