v1.3.2

Minor updates to explore scaleup to runs with 4-8M reference sequences, including:

• Allow use of precomputed bowtie-build directory
• Increased time for ubr_merge
• New ubr_check_run.py allows monitoring of error and output files from cluster runs.
• New ubr_check_stats.py prints out number of reads at each stage of an ubr_run, and is run automatically at end of the run.
• Bug: Need to provide flag --no_collapse or this version won't run. Fix implemented in v1.4.