add getVariable() to util/sql.py

add 4 testcases to query/queryWildcardLength.py

leave a uncorrelated bug ---> TD-5918

* [TD-5844]<feature>: make cmd line parameter similar.

* fix test case align with taosdemo change.

* fix windows stack overflow issue.

* fix mac compile error.

* fix taosdemo cmdline parameter in tests/pytest/tools/taosdemoAllTest/NanoTestCase/taosdemoTestSupportNanoInsert.py

* [TD-3048]<feature>: support lines/stream/query_a/stop_query/ and so on.

commit 0edc106a76a95b28e65019c2ee4e4ed84530ad35
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Thu Jul 29 21:13:13 2021 +0800

    doc: improve document for python connector

commit 84915de0831b49c8378a16242dd0dbba8aaf386f
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Thu Jul 29 20:35:45 2021 +0800

    chore: add time elapsed

commit 1e8822e01bda96388a359363776792e261260b88
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Thu Jul 29 20:26:01 2021 +0800

    feat: support multi bind

commit 82d823f6194471fd3324b50f7dfba0ee9f10a7dd
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Thu Jul 29 16:42:05 2021 +0800

    feat: python support for async query and subscribe with callback

commit 8b9d36de2945906821225189cb47958e153d81e2
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Wed Jul 28 18:09:09 2021 +0800

    feat: finish stream and stmt interface

commit bc871aa43e9fc28dd1b3f8784a8ac6ee988564b5
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Mon Jul 26 20:21:27 2021 +0800

    feat: basic full-fetured implementations

commit e5f7a5213e9016c377a57485e8d5c12139ce0957
Author: Huo Linhe <linhehuo@gmail.com>
Date:   Fri Jul 23 10:33:14 2021 +0800

    tmp: refactor

* chore: fix insert/line_insert.py error

* [TD-3048]<fix>: fix tests error

* [TD-3049]<feature>: support stop_query in python connector cursor

* [TD-3048]<doc>: improve python connector document

* [TD-3048]<doc>: improve python connection README

* [TD-3048]<hotfix>: fix python2 install and runtime error

* chore: replace insertLines with insert_lines

* chore: fix misspellings

* chore: fix crash gen error in threading

* feat: support __del__ method for simplify

* test: fix subscription test result check

* chore: compatible with 2.0.20

* chore: fix python connector subscription test case

* [TD-3048]<fix>: fix schemaless insert test

* [TD-3048]<fix>: fix memory leak in crash_gen test case

* [TD-3048]<fix>: minor fix for crash gen memory leak

* [TD-3048]<fix>: set minimal required python3 as 3.4

* chore: update version in setup.py

* [TD-3048]<fix>: fix runtime errors in python3.4

* [TD-3048]<fix>: add typing as a dependency

fix a small-probability bug for insert/schemalessInsert.py when another random tbname is start with t-->noIdStbExistCheckCase(): where tbname like 't_%'

fix an error in test case about "tao_consume is called too frequently so that the interval between them is less than the interval set in taos_subscribe."

finish 40 cases for schemaless in insert/schemalessInsert.py, but 5 of them could not be used now because multiThreading is not complete

modify util/sql.py: add row_tag in query(), add col_tag in getColNameList(), add checkEqual() and checkNotEqual()

add insert/schemalessInsert.py to fulltest.sh

finish 40 cases for schemaless in insert/schemalessInsert.py, but 5 of them could not be used now because multiThreading is not complete

modify util/sql.py: add row_tag in query(), add col_tag in getColNameList(), add checkEqual() and checkNotEqual()

add insert/schemalessInsert.py to fulltest.sh

finish 40 cases for schemaless in insert/schemalessInsert.py, but 5 of them could not be used now because multiThreading is not complete

modify util/sql.py: add row_tag in query(), add col_tag in getColNameList(), add checkEqual() and checkNotEqual()

add insert/schemalessInsert.py to fulltest.sh