tempfiles

[mmagnuski]

About this PR:

This PR introduces tempfiles - temporary files with filtered & epoched data stored in tempfiles folder. Using tempfiles significantly speeds up recovering files the second time.
Using tempfiles from the command line:

[EEG, db] = recoverEEG(db, 3, 'tempsave');

Infomation about the tempfiles is stored in db(r).datainfo.tempfiles in the database and EEG.etc.temp in the recovered file. So you can add tempfile info to db even if you forgot to get updated db from recoverEEG you can still get it from EEG and save in the db.

TODOs:

• "rooted" paths - for example +tempfiles meaning any valid path from db(r).filepath but with tempfiles folder added to the path end.
• db_gui options to use tempfiles
• function to clear unused tempfiles (from db and from hard drive)
• incorporate cleanlined files to tempfiles logic