[Obo-format] Opinions? Skipping validation for writing obo-format documents

[Chris M. <cjm...@lb...>]

https://github.com/owlcs/owlapi/issues/290

In owltools, it's always been possible to skip validation with "-o -f 
obo --no-check my.obo", which is very useful if you need to defer fixing 
of issues. However, when using from Protege there is no equivalent of 
these options.