Error response javadoc @tag

Allows parsing of javadoc tag to feed "errorResponses" part of swagger api.

Syntax : ```@[annotation_name] [code] [reason]```

Default tags :
- ```@errorResponse``` for swagger 1.1
- ```@responseMessage``` for swagger 1.2

Can be extended by providing custom tags with doclet parameter ```-errorTags myTag1,myTag2,...```