Train regression using multiple channels.

This is from a few weeks ago, may or may not run as is.
Some filters from filterbuilder.
Calculate mean beta/gamma PSDs.
junk
More junk
Committing a bunch of random stuff.
Function to extract features.
Plot log scale PSD in gui.
Function to calculate time indices for extracted features.
Fix feature extraction (NFFT was wrong when calculating bin positions),
add Bash script for batch feature extraction.
Store PSD features in a cell array (per channel)
Fix printing NW in filename
Actually save PSD features.
Stick NFFT and f_s in feature struct.C
Update feature extraction bash script
Fix output file name.
Fix wait position so that multiprocessing can actually happen.
Batch feature extract: Disable JVM, fix PSD feature memory layout.

The cell array in struct thing was causing weirdness - the features
variable became a 1x62 struct array with 62 copies of all the common
features. Derp. Use a 3D matrix instead.
Limit concurrent tasks to the number of cores (rudimentary).
Save files in v7.3 format (HDF5) to allow files bigger than 2GB