v2.4.1

Release 2.4.1 introduces several minor improvements to reading partitioned data.

1. More allowed special characters in partition names. Following characters are now accepted: ?, +, ,, &, $, :, ;, / and . Beware that a file system that you use may not allow such characters in directory names or that they may require special treatment.
2. Do not attempt to read empty directories in Akka module.
3. Minor dependency updates.