osc tuning as fn, to retune if init clock is slow
wk towards log-while-dumping
now logs data through dump
removed some comments, etc.
prelim fast data search (not tested yet)
inserted testing diagnostics
more diagnostics (incompletely tested)
clean up code some
try simpler 'fileExists'; has bugs
fileExistsForDate explict char array
fileExists using f_stat; seems to be working
removed fileExists diagnostics
dataDump, check SD card power before searching
in dataDump, used local var 'errBTDump' in place of file global 'errSD' for all except data logging
try test for power droop during dataDump
removed 'File stat return code' diagnostics from 'datetime_nextDateWithData'
removed other diagnostics from 'datetime_nextDateWithData'
removed diagnostics from 'readStringFromFileFromSDCard'
removed some comments
removed 'stBeginTryDate' diagnostics at end of dump