Widen MockFactoryBase.ExpectationException to Throwable

This lower bound is too restrictive, it prevents for instance the use of AssertionError (if you want to integration with JUnit).
Merge pull request #80 from backuitist/patch-1

Widen MockFactoryBase.ExpectationException to Throwable
Merge remote-tracking branch 'origin/master' into issue_25_fix_squash

Conflicts:
	core/src/main/scala/org/scalamock/MockFactoryBase.scala