Smot

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* remove debugging crap

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* allow factor imputation through patristic distance

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* add power scaling option to samplers
* add grep

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* remove midpoint command - it was too slow to be useful, there are better CLI
tools for this job
* Fix bug preventing STDIN

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* update CLI interface
- subcommand documentation
- documentation for each field
- cleaner argument checking

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* allow automatic reading of NEXUS
* remove '--format' option (infer input format and write newick)
* add BioPython-based convert function
* let factors be appended or prepended to tip labels
* merge sampling commands
* ladderize tree before plotting
* `clean` command also ladderizes the tree