Prerequisuites to Reputation api support

See merge request !121

Enabled concurrent flush of Follow objects.

update in CI - tags_api has negative group, while old .yaml is no longer present

See merge request !126

Follow data shall be flushed also from Blocks.process level which is used at...

See merge request !125

changed behaviour of some condenser_api calls: when start_author or start_permlink is present, they need to point to correct post or error is generated
fixed crash when start_author or start_permlink is passed to some condenser_api calls

Follow data shall be flushed also from Blocks.process level which is used at regular block listening path.

Remove FKs before initial sync and recreate after initial sync

See merge request !124

Fixes around post data edit

See merge request !120

Fixed edit case with empty title, body or json_metadata
Fixed use of json - now everywhere ujson is used
In case json_metadata in comment_operation would not actually be json, HiveMind no longer crashes on access
Since we are handling bad json anyway it was no longer needed to fill empty json_metadata with {}, original empty string restored

Avoiding a redundant loop during `effective_comment_vote_operation` processing

See merge request !116

Teh call `get_profile` works

See merge request !110

Some characters apparently need long 8-byte encoding

See merge request !117

[ABW]: some characters apparently need long 8-byte encoding (problem actually caused by use of ujson)

Unified some error messages and added CI groups for tests made in new scheme

See merge request !114

added new test groups to CI with at least single test to make it easier to move tests accourding to new scheme (only follow/tags have no negative tests so no such groups were added)

Database api fixes

See merge request !103

fixed unicode escaping

See merge request !113

[ABW]: added separate tests to CI (all tests will eventually be run through folders instead of common .yaml file)

Add num_block to tables, add proper reblog support

See merge request !112

tests/tests_api submodule changed to introduce get_discussions_by_blog testcases.

See merge request !111

* Added num_block to hive_follow and hive_reblog tables,
* Added reblog class to process reblog operations,
* Sync will now show version info, git revision and db version on start

Eliminated obsolete columns from hive_posts: author_rep, url, root_title

See merge request !109