1. Wrote function and documentation for abbrev() which abbreviates school names by taking the first capitalized letters of each word (i.e., words not in title case are ignored); you can also pass the function a list of exceptionsto the natural abbreviations  (see examples in .Rd file, but to give a sense, at KIPP Chicago our pimrary school's name is KIPP Ascend Primary Schools which is naturally abbreviated as KAPS, but is ubiquitously referred to as KAP.  You can pass a list with 'old' like KAPS to be replaced by 'new' names like KAP).  2. refactored all the aggregatioin and summarization code in becca_plot() to use data.table making the code shorter, more readable, and faster. I still need to fix the location of labels and bar widths. 3. updated DESCRITPION and NAME space to import data.table.
Should we automatically add justifications based on max and min grade-seasons?
Added abbrev funciton code and documentation (forgot to add in the prior commit that mentions them).
Finally added abbrev.Rd