Adding FeatureFileSearch

Ami44 suggested in https://github.com/acuminous/yadda/issues/47 that
FileSearch should default to *.feature files, however this would
since file search is generic, I created a specialised FeatureFileSearch
which expects *.feature, *.spec and *.specification instead
Examples install yadda using npm link

Previously the examples installed yadda using npm install.
This meant they didn't automatically pick up changes to
yadda. Using npm link fixes this.
Preping for 0.9.4
Annotations with non alphanumerics are normalised

Also removed a console.log
List undefined and ambiguous steps (see issue 30)
Bundles
Merge branch 'master' of github.com:acuminous/yadda