Add CSV support to upload function

[lilchurro]

Allow user to upload a CSV file; convert it to json format and feed it to CRviz.

[lilchurro]

Implemented in pull request #58

[lilchurro]

As there are some issues (see: issue #60) with the current implementation, I'm reopening this enhancement ticket for more detailed planning. Currently, I had done some basic parsing and verification on an imported file, and then passed the contents on to JSON.parse if parsing as CSV didn't work out. The result was the user wouldn't really be notified about formatting errors from the CSV file, and complicated data types (i.e., quoted field values, in this case) weren't really being parsed properly.

All this to say, adding native CSV support is actually rather nontrivial, so I'm reworking the code to provide better support for this functionality.