Incorporate automatic conversion of JPG/JPEG/PNG to TIFF prior to passing to OpenSlide

[sarthakpati]

Put this check 2 places:

• OPM/opm/patch_manager.py

  Line 19 in 8abc8db

  self.slide_object = openslide.open_slide(filename)

• OPM/opm/patch_manager.py

  Line 46 in 8abc8db

  self.label_map_object = openslide.open_slide(path)