Add more pure Scala libraries to the benchmarks

[nrinaudo]

Libraries that should be included, if they pass tests, are:

• ~~scala-csv~~
• PureCSV (currently fails tests, but it should be possible to get it to work)
• Delimited
• mighty-csv

There are probably more out there

[nrinaudo]

scala-csv is now supported.

[nrinaudo]

Delimited hasn't been updated in 2 years, it looks like a dead project.