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.
> What's the difference? I guess I can. FYI, this is how it is done somewhere else in the code as well.

Yea not sure what I was thinking. Feel free to ignore :)
I think I was thinking in terms of error message clarity, to first rule out the most obvious errors, but it doesn't matter

> This way, error handling will be consistent 

+1