ported code from a fork of my gregcaporaso/microbiogeo repo

never actually merged that fork into microbiogeo as it makes more sense for this code to be in QIIME
added myself to the credits
changed import mechanism
fixed error introduced in my last commit
updated to hook simsam_range up to the command line
updated tests to use new output file names
added usage example
updated documentation and function name
added ability to override the 'basename' for the output files
updated script to override table and map basenames
added failing tests - issue caught by @jrridout
fixed typo
fixed bug in formatting of mapping file
improving naming of output files
Merge pull request #792 from gregcaporaso/issue-789

addresses #789