insertSeparators: insertSeparators inserts the character "-" between year and month and
between month and day portions of a date string in %Y%m%d format.
Description
This function is not exported because it is not general purpose and
is missing several defensive programming measures.
Usage
insertSeparators(dates)
Arguments
dates
character vector of potential dates
Value
A character vector of potential dates in %Y-%m-%d format.