Obfuscate password

Obfuscate passwords using base64 encoding w/ hashes for verification (and plaintext backwards compatibility!)

Obviously this is *not* a good way to protect passwords; it's only intended prevent others from casually observing your plaintext password on the filesystem. No such assumptions of security should be made, especially concerning individuals that may be fluent in base64.

Initial support for the Socialcast password -- other keys could be added.
this encode call is probably what i'm most uncomfortable with in this PR.

Base64 and Digest::SHA1 appear to prefer US_ASCII (at least on my system ?):

    2.1.1 :003 > Base64.encode64("foobar").encoding
     => #<Encoding:US-ASCII> 
    2.1.1 :004 > Base64.strict_encode64("foobar").encoding
     => #<Encoding:US-ASCII> 
    2.1.1 :005 > (Digest::SHA1.new << "foobar").to_s.encoding
     => #<Encoding:US-ASCII> 
    2.1.1 :006 > "foobar".encoding
     => #<Encoding:UTF-8>