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

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)

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

- removed tests_require from setup.py it is depreciated in favor of tox
- setup test env in tox
- removed gitpython dependency

- CI full process (sync and testing) shall be automatically started also for commits targeting develop and default branch
- ci_sync.sh shall also try to terminate running server before another sync.

- Improvements on error checking in CI scripts (pipe failure shall be detected)
- Improvements on killing previous processes running for given branch.

Defined environment stopping action

Separated hive sync process from hive server - splitted into 2 separate jobs to make possible running them independently (i.e. just restart rebuilt server without sync)

Added git versioning to the build process