New features

Here are the new features I mentioned. Specifically, they are:

-in "Ramp", added checkbox to use the parameters of process 2010.
-In "Ramp Multiple", added checkbox to use the parameters of process 2010.
-in "Deflicker", added checkbox to use the EV parameters of process 2010.
-in "Deflicker", added checkbox to save the EV deflickering data to an external JSON file.
-Added a new "Undo" feature. Before each action, it will call this function to save the current metadata in an external JSON file ("undoData.json"). Afterwards, you can pick in a dropdown menu the action you want to go back to.

Some notes:

-My functions and variable names are in spanish. Hope you don't mind :-), but I can change them if you want to.
-There are specific places where I need to get a list of all pictures in a given folder, but exclude all non-picture files. Right now, the code that does this only detects Canon CR2 files (extension "cr2"). It would be good to find out the extensions used by other cameras (Nikon, etc.), to add them to the code.

If you have any other questions, feel free to ask.