1st working version - two different methods for just one year's worth of data
Looping through files almost working…still figuring out column names
dealt with issue of different columns containing relevant delay data in the monthyl .csv files
first working loop over several files!
table merging function is working (and is surprisingly fast)
corrected problem where I was extracting the wrong column for the monthly files
working functions for mean, median, and sd more or less done
several bugs fixed where the monthly files had different values (i.e. floats instead of integers). Have an answer for mean, median, and sd on the entire dataset.
added a few debugging tests and tested median function more
assignment1.R cleaned up (comments added, and random code from testing and debugging was moved to assignment1notes.R).  README.md was added to describe the method and summarize the results.
added code to create graph of mean delays by year.