In TextColumn, calling appendCell(string, parser) failed because the results of the call to parser.parse(string) was passed to appendObj(), which called parse again, this time using the default parser. This is fixed.

This commit also makes it possible to directly set the missingValueStrings list in a custom parser.

* first commit

This branch is for evaluating the possibility of using ColumnPrintFormatters to optionally format output.

There will be a writeOption called ```usePrintFormatters(boolean)``` that turns the logic on or off. It will be off by default, matching the current status.

The print formatter is set on the column and would then be used by both table.print and table.write, providing more consistent output

PrintFormatters have the advantage of handling missing values so the user does not have to worry about them blowing up a Java NumberFormatter for instance, while allowing the user to set the missing value symbol for each column.

* Added some tests for print formatting for IntColumn and DateColumn

* Creating a class hierarchy for the existing Column Formatters. Additional tests, renamed methods

* fix a few issues. added a test for formatting booleans

* More tests

* addressing some sonar warnings

* Fixed latent NPE in InstantColumn

added test for InstantColumn formatting
removed TODO

* Simplified method in CsvWriter

removed one unused line

* Update CsvWriter.java

* add a test to show it can avoid scientific notation

* implement suggestions from code review

Change System.lineSeparator() for a constant to be less verbose
Change mockUrl to be able to use URLs