@tzcoolman this change still makes the cmdline behaviour inconsistent with other subcommands (one displays help, the other doesn't):

```
(facs)[roman@biologin facs 0]$ ./facs build

Usage: ./facs build [options]
Options:
        -r reference FASTA/FASTQ file
        -o output bloom filter file
        -l text file containing all reference files, will build individual bloom filters for each
        -k k-mer size, default is automatically estimated from the reference file
        -e allowed false positive frequency, default is 0.005


Please, at least specify a reference file (-r) and an output bloom filter (-o)
(facs)[roman@biologin facs 0]$ ./facs query

Please, at least specify a bloom filter (-b) and a query file (-q)
```