Updates for qiime-tools 1.1.3

barcode_filter.py: added an if condition for checking is quality data file is supplied by the user.
biom_relative_abundance.py: imported biom_calc, updated the function to use the newer version of relative_abundance() function form biom_calc.py.
biom_calc.py: updated relative_abundance() function so that it calculates the data for all samples of a biom file. Function takes only one argument now (biom file).
test_biom_calc.py: updated the testing scripts for the newly updated biom_calc scripts.
Updated iTol script to accommodate raw calculations based on OTUID's instead of SampleID's.
PCoA, PCoA_bubble and restrict_repset edits are from syncing the fork. No changes were made from my end.