#50 Feature: implement load test data in yaml format

[Scorpibear]

Implement possibility to load test data in yaml format. This is much more convenient than Excel tables usage, if there are a lot of not related test data.

Example of such test data:
erd_080_product:
"women 160x600"
erd_081_products:
["food 160x600", "women 160x600"]
erd_082_attribute:
{"Ad Size": ["300x250"]}
erd_083_attributes:
{"Inventory Provider": ["HowStuffWorks.com", "ABC7News.com", "SiliconInvestor.com"]}

Requested by Sergey Gvozdyukevich.