#98 Add skipRegex connection property

[Simon Chenery]

Add database connection property skipRegex, defining one or more regular expressions of lines in the CSV file to skip.

This enables unwanted lines in the CSV file to be skipped (for example: empty lines or metadata information lines) and is more general than the existing commentChar property.

[Simon Chenery]

An example regex that would skip empty lines and any line beginning with a hash or two slashes is:

^(//.*|#.*|)$