Changed comment for the client secret.
Extracted duplicated code from all services into factory class for Exception construction.
Added httpStatusCode property to ConstantContactException.
Updated SDK version in pom file.
Merge pull request #36 from halusstefan/master

Latest changes HTTP status code propagation + changed comments.
Updated docs.
Merge pull request #37 from halusstefan/master

Updated docs for version 2.1.4