[COLLECTIONS-540] Added CollectionUtils#get(Enumeration, int), simplified code of CollectionUtils#get(Object, int). Thanks to Daniel Stewart, Issam El Atif. This closes #6.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/collections/trunk@1647955 13f79535-47bb-0310-9956-ffa450edef68