Pickle the HDTV Phase I data

[Qub3k]

Using the export functionality (that will be) implemented in #14 store the HDTV Phase I data in a pickle file. Importantly, the pickle should contain data as Pandas DataFrame object(s).

The frist step is to retain information about PVS -> Subject -> Trial/Score mapping in the output DataFrame (see the 5th slide of this presentation).

• [x] @awro1444 exports the sujson dictionary to pickle (i.e., without converting to any other data format)
• [x] @Qub3k and @awro1444 design the suJSON -> DataFrame(s) mapping
• [x] @awro1444 Implements the mapping

[Qub3k]

stimulus_id	subject_id	trial_id	score
1	1	1	5
2	1	2	3
1	2	3	4
2	2	4	3

This is how the very first output DataFrame should be structured.

Note that Stimulus = PVS. We use stimulus to make it easier to understand that PVS does not have to always correspond to an image or video.

EDIT: I've renamed the columns to better reflect their meaning. Please also notice that the trial_id column stands for something slightly different than previously. (Now, no repetitions are allowed in this column.)

[Qub3k]

There is a related pull request (cf. #16). I am in the process of reviewing it and merging with the master branch.

[Qub3k]

Since @awro1444 made a first attempt at storing the data as a *.csv file (in order to make it readable from Matlab) this issue is now related to issue #6. We should consider merging the two issues.

[Qub3k]

Since #14 is not yet completed this issue is still opened. (We keep working on making sure the sujson._sujson.Sujson.pandas_export function works properly for the representative suJSON file.)