- updated documentation, add list of supported protocols
- renamed `tagged_bams_in` to `mapped_bams_in`
- added check to make sure only one input directory exists
- added check to confirm that `use_raw_reads` is set when using `unmapped_bams_in` or `mapped_bams_in`
- add link to cluster log documentation when showing error message
- internal changes:
+ made input rules conditional on input directory existing, to remove some ambiguity when input files are missing
+ make sure `stats_alignment` files are created even with `mapped_bams_in`
+ added test for multiple input directory check