Absorb extra whitespace when parsing field names

I had an issue where I had two spaces after my comma in a --field list.  This caused lots of problems when my database column was created with a leading space.

A straightforward solution is to modify the RegEx for the preg_split functions.
Change the '?' (Match 0 or 1 instances of the preceding character) to a '*' (Match 0 or more instances of the preceding character).  This will ensure that any leading/trailing spaces will be absorbed by the split command.