Backporting Geoserver's CSVDataStore updates to Geotools

Adding the updated CSVDataStore to geotools. The code is nearly identical to geoserver's fork, with the exception that the test cases are updated to use geotools' test data. The goal is to remove the duplication of this data store, so in the future geoserver can pull in the module as a dependency.
This is going to be a mess due to the nature of forking code.

We need to communicate what happened with license and what happened with date:

1. Original was public domain for use as a tutorial (date created?)
2. Fork was made at Open Plans (date is not 2001-2013 we will need to check history to see when importer was created).
3. When we have permission the result will be LGPL (date will be 2014)