benchmarking, but introduced a bug and added two tests which currently fail.
passed all tests, but then vignette building broke with more examples. WIP.
tidied up F, FALSE, etc and whitespace. Moved planned work to README.
removed debug code from test-ICD9
rename icd9 test to lower case
export S3 methods for icd9Explain, simplify start-up message, alow one of the icd9 source files to read as ascii