Downsampling all data and storing it

[vincentadam87]

From the initial competition,it appeared that a sampling rate of ~400 was enough to achieve very good performance.
Given we now deal with quiet (= even smoother) segments, this still certainly applies.

Therefore, to save time, on could have a set of folders containing the same data (mat files) but downsampled.

This could actually also include the electrical noise filtering (although a few checks are required)

[vincentadam87]

done!