save df3d output to behavior

[azmaite]

Currently the output of df3d is saved inside the images folder (behData>images>df3d). This makes it very annoying to access when all the videos are saved as individual images in that same images folder
The df3d folder should be saved instead inside of behData but outside of images.

[jasper-tms]

Here are the relevant lines, I think.

DeepFly3D/df3d/core.py

Lines 70 to 72 in d8f4b88

	self.input_folder = input_folder
	self.output_subfolder = output_subfolder
	self.output_folder = os.path.join(input_folder, output_subfolder)

You can try just changing the third line to be self.output_folder = output_subfolder and I think that will get rid of the fact that it nests the output folder within the input folder.

This will almost certainly break some tests that assume the output folder will be inside the input folder, but generally I agree with you that it's annoying that the output folder goes inside the input folder instead of next to it.

[azmaite]

This didn't work and I think it would be a problem, as the default output_subfolder is just 'df3d'.
Instead I changed it to the following, so it saves it to behData/df3d (or if you specify an output subfolder, then behData/output_subfolder). I'm testing it now but I think it should work.

 self.input_folder = input_folder 
 self.output_subfolder = output_subfolder 
 behData_folder = os.path.dirname(input_folder)
 self.output_folder = os.path.join(behData_folder, output_subfolder)