Enhancements for mongoexport CSV output

The mongoexport tool's CSV output feature is great but it generates data that is hard for external tools (e.g., Excel, etc.) to parse. The following enhancements to CSV output would make mongoexport an extremely powerful data export tool:

1. Allow string formatting of date fields by allowing a date format parameter to be passed in. The current

format is not understood by external tools like Excel.

2. Allow list fields to be formatted to a string using a specific delimiter. E.g, a pipe character delimiter would convert the following values:

[ 1, 2, 3 ]

To:

"1|2|3"

The converted list field's data would be wrapped in double quotes to make parsing easy.