util: get_taxonomies
util: improved taxonomy getting
tests: corrected import name
uc2denovo: a new script

It's for getting the unmatched sequences from the uc file to be set up
for a denovo clustering
tests: correc uc2otus, refactored
uc2denovo: small fixes
otu: added open-reference option
cfg: updated name of the library in the config file
otu: finished the open reference steps
otu: moved unsplitting into quality filtering

this way you can feed a single fasta file into the dereplication step
new file: added qiime label converter
Merge pull request #10 from swo/master

beta open reference calling; improved tests; new utilities