New token parser implementation partially based on Mime4J code (written by me)

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk@1615885 13f79535-47bb-0310-9956-ffa450edef68
Changed BasicHeaderValueParser to use TokenParser for header element parsing

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk@1615886 13f79535-47bb-0310-9956-ffa450edef68