Change RSACrypto and KeyDictionary to be Public

We use these classes in SteamBot, and I'd much prefer to not have to add
modifications to SteamKit before we can use it with SteamBot.  These
classes are used to log in with their API interface
(ISteamUserAuth/AuthenticateUser).
Adds Requested Documentation
Merge pull request #2 from redjazz96/public-utils-fix

Change RSACrypto and KeyDictionary to be Public