This is a patch to make the encoding specified optional again. If not specified, it will default to the users setup for file encoding.
It might be nice if we could determine the encoding of the file they are training with and appropriately select the correct encoding. But, we can't have everything.
a) Adds a detail description of all the options currently specified.
b) Removes the null test before training,
c) and adds the tests for null to use the user default encoding (specified by the OS and installation)