#19 Add fine grained exclusions

[Vincent Massol]

It would be nice to be able to use Clirr to fail the
build if a breaking binary change is introduced.
However this needs the ability to specify when a
breaking change is introduced voluntarily. This could
be implemented as an exclude feature. However the
current exclude feature excludes a full java class. We
need something more fine-grained, i.e. the ability to
exclude a clirr check (both from a file and from
several files at once)

See http://tinyurl.com/kb7dm (post entitled "Blog post
on Clirr...").

This would allow implementing the strategy defined on
http://tinyurl.com/84lbb

Thanks
-Vincent