First pull request!

I just realized I needed to inititiate the pull request on github (and that pushing from the command line wasn't enough).  So here it us.  I refactored becca's plot and added an abbreviate function abbrev(), that take exceptions (i.e., here in Chicago we have a school KIPP Ascend Primary School that "naturally" abbreviates to "KAPS", which nobody ever refers to it as.  Instead they call it "KAP", so abbreviate will do the natural abbreviation first, and then look un a list of wrong:replacement key:value pairs  (wrong is based based on the natural abbreviation) and update the replacements.  Right now it exported as an function avaible to all users, but should probably be made an internal to the package function.