routes.rb-like targets for events

Add capability to specify the target for an event in a fashion similar
to the one used in routes.rb, e.g. "product#new_product". Added
examples to event_map_spec to test new functionality
Added helper class and matchers, specs missing
Extracted validate_xxx_options to a separate TargetValidator class which can be reused fro other parts of the code. Added spec for TargetValidator.
Added spec files to demonstrate the usage of new matchers and helper classes
Update README.md

Added explanation how to use the new syntax
Merge pull request #41 from nessche/routes-like-event-targets

routes.rb-like targets for events
Merge pull request #42 from nessche/improved-spec-helpers

Improved spec helpers