Validate 'markers' order in cfg.spec is same as in reference file

[epogrebnyak]

The algorithm may break if markers (start and end lines) are not in order, to check for that:
- must read csv file rows, use a reference csv file (use files.get_latest())
- use first pair in start and end markers
- make sure the order of markers in specification is the same order as in csv file

Need addition to test_cfg.py or validation method in cfg.spec: