fix importer: now correclty handles double quote encapsulated commas

Changed the way the string splitting occurs, instead of a simple split on "," detect if there are any embedded commas inside double quotes. If so, build the string list correctly respecting the double quotes. As a minor issue, we will need to consolidate the way the different classes do the string splitting, as you can see in this commit there are two functions which do the same task. ParseLineIntoColumns in RawFileReader.cs and parseTestLine in CollarImport.cs