Exact match for groupId excludes

Previous to this commit, any groupId starting with one of the
configured exclude would be excluded as well. This potentially
leads to unintentional dependency filtering: for example the
GroupIdFilter with an exclusion of "org.springframework"
also removes "org.springframework.boot" dependencies.

Add MatchingGroupIdFilter that uses an exact match instead.

See #649
Merge pull request #899 from markdingram/master

* pull899:
  Exact match for groupId excludes