Implement all RDP, GG, Silva and UNITE taxonomies to dada2.R
Implement all RDP, GG, Silva and UNITE taxonomies to dada2.R

Dada2 can taxonomize results using Silva, RDP, GreenGenes and UNITE
databases. Only Silva was used in older versions. To implement RDP,
GreenGenes and UNITE in next version, `dada2.R` script must be able to
accept paths to all databases and save results in format that can be
easily parsed.

- Add new parameters accepting paths to all RDP, GreenGenes and UNITE
databases
- Save results from `dada2.R` script to tsv files.

vrbacky/proceseq_16s,vrbacky/proceseq_16s