Trim field values by default

[reckart]

Some people have broken CoNLL files which include leading/trailing space characters in fields (non-tab). To make the readers more robust, we could by default trim fields to remove leading/trailing space.

However, this should be an option that can be turned off just in case somebody actually wants the space to be there.

[reckart]

User comment:

I think that an error message or at least a warning at the import step would be more useful than a trimming of the data.