add more SOCR datasets

[alxndrkalinin]

SOCRAT provides few predefined SOCR datasets, like Iris (here's how to use them locally). This task is to make more SOCR Data available via SOCRAT.

List of datasets to add:

• BMI Regression
• nfantVitK
• JobsRanking
• Elect
• Brain2BodyWeight
• SupperLotto

Subtasks:

• [ ] create separate data branch in your Github repo and synchronize it with SOCR/SOCRAT:dev
• [ ] save each data table as .csv file (e.g. using Excel or Google Spreadsheet) and place it under _build/datasets in your local SOCRAT directory (don't use spaces in the filename)
• [ ] add your datasets into the list of available SOCR datasets with meaningful name and correct URLs to the file and SOCR Data description page
• [ ] test locally that loading each dataset and opening descriptions works correctly
• [ ] commit changes following commit message format
• [ ] place created .csv files on GDrive under SOCR_MDP_2017/SOCRAT/datasets
• [ ] submit a Pull Request to SOCR/SOCRAT:dev mentioning what datasets you added

Note: if your dataset page contains multiple tables, add them as separate datasets (description link can be the same)