Handle MIME media types which have charset param - fixes #685
Don't guess field widths unless we have at least 3 lines
- Investigation of #685 showed that single line files were being guessed
as fixed field width
Replace Jython JAR with one that includes all libraries - fixes #693
Report Jython errors to user - addresses #694
- may need to work on the format a bit more
Clean up a couple more format guessing issues left over from #685