When recording macro commands, pay attention to single backslashes.

As pointed out by Miquel Banchs i Pieque and Niko Ehrenfeuchter, in Windows systems it is necessary to record the single backslashes as double.
Substitute slash character by File.separator to prevent errors in Windows systems.
Remove commented code.
Apply 8-bit conversion and LUT to result image.

When applying a classifier from macro, make sure the result is in 8-bit and with the same lookup table as in the GUI.

TODO: use the same method from the GUI and the macro. As it is now, the GUI accept a list of images but the macro command processes only one.
Make release 2.1.1

Major changes:
* Fix bug concerning backslashes in paths using Windows.
* Show 8-bit color results from macro when applying classifier.
* Update buttons enabled when loading classifier from macro.