Parse multi-value columns

[mstreit]

The importer should be able to load data for the multi-value renderers (heatmap, sparkline, etc. - see Caleydo/lineupjs#145). Hence, a cell in the input CSV file can contain an array that uses a different separator.

[bikramkawan]

I have added the multi-value data for parser. The structure of multi-data for now is [1,2,3,4,5]. The edit dialog looks like:

and after the importer looks like

[mstreit]

The user does not need to specify the sorting criterion in the import dialog because it can be changed interactively anyway.

Why is it necessary to specify the data length? This should be already known after parsing.

[bikramkawan]

Yes, the parser knows already. So I will then just remove from the edit dialog.

[bikramkawan]

Fixed parser in importer before feeding the multivalue in line up renderer.
The dialog is also corrected and added threshold.