avoid crash from non-data items in Hoboware txt file, but bad items end up in DB
essentially same header workaround as Tanya's; now try to catch non-data too
Data table CHECK now disallows any Value not a FLOAT
distinguish different kinds of sqlite3.IntegrityError
further distinguish ItegrityError
only count 'not unique' errors, ignore 'constraint failed'
simplified, no output if just junk data
copied error checking detail to other functions
merge branch 'master' into 'ignore_nondata', which had become de-facto master