* add cassandra extractors, tests and docs

* add cassandra extractors, tests and docs

* code refactor based on pr and code linted

In practice, when requesting logs going back more than a few days, the
StackDriver API sometimes responds with an empty page with a next page
cursor. After polling the next page a few times you eventually start
getting entries. The empty pages have no `entries` key, which previously
resulted in a KeyError.

This change allows the extractor to continue polling instead of blowing up.

* glue_extractor scope refactor to glue and filters option add

* README refactor to explain glue configuration

* Mark sort_order col so Publisher leaves unquoted.

* Add UNQUOTED for sort_order to unit tests.

* Shorter lines for the flake8.

PyCharm's highlights were very confusing.

* Fixed Snowflake views being captured as tables

Updated snowflake_metadata_extractor.py and fixed that Snowflake views were captured as tables.

* Fixed unit tests for snowflake metadata extraction

* Fix lint error

This involved adding schema_name to table_stats model as well as float and int columns to sample data

* add aws glue extractor

* add sample code for glue extractor on README

* patch whole glue_extractor test to avoid boto3 error if not configured

* boto3 add on requirements

* Prevent empty table tags appearance

* Prevent empty table tags appearance

* Add sample table tag data to quickstart

* Add sample table tag data to quickstart

* Add sample table owner data to quick start (#139)

* Update example/sample_data/sample_table_owner.csv
Co-Authored-By: jornh <jornhansen@gmail.com>

* Add sample table owner data to quick start

Will scroll past GitHub repo folders (specially more handy on small screens like phones/tablets)

* Add sample high/low watermark data to quick start (#62)

* Update setup.py

* Relax dependency to make it range

* Update requirements.txt

* set field_size_limit to max

* fix lint

* increase version

* update

Removed `SQUASH COMMIT` from the PR template

* Make some unittest work with py3

* Make some unit tests work with py3

* Make snowflake metadata extractor py3 test green

* feat(user): add Neo4j to ES quickstart sample job

* lint

* Fix (user): Whitespace glitch giving quotes in UI

* Correct ES mapping, thanks Tao!

* lint

* Trailing Linefeed

Check for a valid string on the regex transformer.  If not a valid string, then the value is ignored and the original record returned. (#136)

* Add Snowflake Extractor

* Move default value

* Add Snowflake extractor