I-08 Improved import of ASCII results

import of ASCII results is currently channel wise by manually selecting files
this is cumbersome and prone to errors
ASCII files which are not an image (e.g. data traces) cause an error which aborts the input
this issue is related to issue I07
To Do
select only a folder for import, FLIMX has to find files and channels for import
ignore incompatible files (give warning to user)
show a preview of the to-be-imported data using the import wizard or something similar
preserve the ability to manually add files and/or channels the same way as before
preserve the ability to load images as masks alongside the ASCII results and add the ability to choose image import as binary mask (with user defined thresholds) or as image data (RGB images for each channel or the combined image)
enable renaming of additional parameters and image masks

M-Klemm / FLIMX