Save files and still be able to use the database

[mmagnuski]

Just like when ICAw_cleanline is run - files are saved and the database is reformatted (some info goes to datainfo etc.).

Although filtering and epoching etc. does not take long - in some cases it can take 5-10 seconds while loading a filtered and epoched file would be much faster. Also - we should remember than it would be definitely longer with 1000 Hz file for example or with much more epochs than 400.

• It should be optional to save files at some point and continue on the saved files.
• operations performed so far on the files should be moved to datainfo
• If files are saved as epoched and filtered - changing these fields should not make any effect.
• Going back to the original file with changes performed (like - marks, rejections) should be possible.

[mmagnuski]

Full going back may not be required for v 0.1
Just make the basic stuff work.

[mmagnuski]

#80