MIME4J-241: inconsistent StringInputStream read zero behavior

git-svn-id: https://svn.apache.org/repos/asf/james/mime4j/trunk@1606057 13f79535-47bb-0310-9956-ffa450edef68
Added builder class for Message instances

git-svn-id: https://svn.apache.org/repos/asf/james/mime4j/trunk@1606062 13f79535-47bb-0310-9956-ffa450edef68
Minor code refactoring and cleanup in MessageBuilder; SingleBodyBuilder to use BodyFactory to instantiate TextBody and BinaryBody

git-svn-id: https://svn.apache.org/repos/asf/james/mime4j/trunk@1606167 13f79535-47bb-0310-9956-ffa450edef68
Moved common MIME entity building logic to a separate class

git-svn-id: https://svn.apache.org/repos/asf/james/mime4j/trunk@1606454 13f79535-47bb-0310-9956-ffa450edef68
Added builder class for BodyPart and Multipart instances

git-svn-id: https://svn.apache.org/repos/asf/james/mime4j/trunk@1606455 13f79535-47bb-0310-9956-ffa450edef68
Extended new builder classes with methods to create copies of message elements and to parse message from content stream