HSEARCH-1755 Making sure that DefaultStringBridge has a public no-arg co...

...nstructor

Also allowing the use of @Factory within a FieldBridge. This opens the possibltiy to re-use singleton instances,
even if @FieldBridge is used to specify bridge class.

Renaming some of the methods in BridgeFactory.
Could you invoke the factory method only after having validated the number of annotated methods?
Bonus points if you add a meaningful error message for A) the method not being accessible B) not having a zero-parameters signature C) returning a wrong type D) returning null E) wrap any runtime exception it might trigger on invocation