Scanning files for a collection should be generalized to `.las/z` files

[brycefrank]

pyfor/pyfor/collection.py

Lines 36 to 37 in 091a666

	las_path_init = [[os.path.join(root, file) for file in files] for root, dirs, files in os.walk(las_dir)][0]
	las_path_init = [las_path for las_path in las_path_init if las_path.endswith('.las')]