Merge pull request #1 from germangh/master

Support for meegpipe .pset/.pseth files, reads faster mff files
small fix to scorestatistics
Merge branch 'scorestats'
add additional preferences
added opt_default, with no info apart from the minimum to construct window
more robust handling of opt files, it should not ask the user to choose opt file if the previous optfile was opt_default, and some other elements to make it more streamlined
bug fix: when we had only one channel as reference, re-referecing took the mean over time, instead of over the only one channel