#46 Create filenames according to input files like Hugin

[John Doe]

Hugin automatically derives a filename from the input files. Luminance HDR should behave the same, i.e. use a combination of the original filenames instead of "Untitled".
Preferrably it should be "intelligent" like Hugin. Example: Original filenames: IMG_0.jpg, IMG_1.jpg, IMG_2.jpg. Automatically generated filename: IMG_0 - IMG_2.exr