when header block would not match blocks in the stream
when Const column is present.
* Updating 00963_temporary_live_view_watch_live_timeout.py
and removed timeout=5 after WATCH query is aborted with Ctrl-C
so that the default timeout of 20sec is used
* Small style fixes in tests
* data race condition on storage is_dropped access
* invalid reference to storage after it is deleted
* invalid reference to mutex after storage is deleted
and making the setting to be in seconds instead of usec
* Updated LIVE VIEW table to keep version consistent as long as the server is up
* Removed calculation of hash in writeIntoLiveView method as it is recalculated
in the LiveViewBlockOutputStream
* Changed to using values from the local context for live_view_heartbeat_interval and
temporary_live_view_timeout instead of the global context
* Updated LIVE VIEW tests to match the changes
* Adding support for watching live views via HTTPHandler
* Small fix to WriteBufferValidUTF8.cpp to propagate next() call
* Updated copyData.cpp to treat block with no rows as
"flush block"
* Updated PushingToViewsBlockOutputStream.cpp to directly use
LIVE VIEW output stream instead of calling its write method
