OPTIMIZE doesn't produce intersecting merges now, add optimize_throw_if_noop setting. [#CLICKHOUSE-3432] [#CLICKHOUSE-3420]

Resolves #1753

Fixed handling of obsolete parts.
Fixed conflict resolution between simultaneous PreCommitted covering parts.
Fixed memory leak caused by ordinary MergeTree parts stucked in Deleting state.
Added hidden _state column into system.parts.

Explicitly disallow dummy data types and special Null data type to be in table declaration [#CLICKHOUSE-4].

* ReplicatedMergeTree: Max streams to send data [#CLICKHOUSE-2878]

* fix

* better messages on client

* change code to 429 TOO_MANY_REQUESTS

* wip

* better message

* Update InterserverIOHandler.h

* Update InterserverIOHTTPHandler.cpp

* Update StorageReplicatedMergeTree.cpp

Apply in a loop:
find dbms -name '*.h' -or -name '*.cpp' | xargs grep -l -P '^(\t*)    ' | xargs sed -i -r -e 's/^(\t*)    /\1\t/'

* introduce ZlibDeflatingWriteBuffer and ZlibInflatingReadBuffer
* use them instead of Poco streams
* seamlessly uncompress multiple concatenated gzip streams