maxLength ignored during delimited bean writing #96

I am using BeanIO to convert a bean (with a number of sub-records and so on) 
into a pipe-separated value string. However, the inputs to this bean aren't 
guaranteed to line up with the maximum lengths allowed at the other end, so 
some validation needs to occur.

I have set the max length property in the @Field annotation, but it's being 
completely ignored during the writing of the bean - if I set a value of "ABC" 
on a field with a maxLength of 1, I get output like "...|ABC|...", which isn't 
what I want. I would prefer that it is either trimmed, or, preferably, rejected 
with an exception. If needed, I can attach some sample code to demonstrate the 
issue.

Checking the code, Field simply doesn't perform any of this checking when 
marshalling. I had a look at perhaps doing it in the same way as the 
unmarshaller does, but I'm not sure if that's a good idea (would also require a 
bunch of copy-paste coding).

Incidentally, I would also prefer it if during any bean writing, it threw an 
exception if the value was longer than the length or maxLength of the field - 
silently trimming it for Fixed-length records and ignoring it for delimited 
records is (A) inconsistent, and (B) dangerous, at least in my mind. I can 
raise a new issue about that, if you prefer.