Commit the cryptrand project worked on in git:

Commit the cryptrand project worked on in git:
- MWCryptRand: A new api for generating cryptographic randomness for security tokens. Uses whatever cryptographic source is available and if not falls back to using random state and clock drift.
- wfRandomString - A simple non-cryptographic pesudo-random string generation function to replace wfGenerateToken which was written pretending to be secure when it's really not.
- Core updates to use MWCryptRand in various places:
-- user_token generation (to do this we stop generating user_token implicitly and only generate it when needed to avoid depleting the system's entropy pool by reading random data we'll never use)
-- email confirmation token generation
-- password salt generation
-- temporary password generation
-- Generation of the automatic watchlist token
-- login and create user tokens
-- session ids when php's entropy sources are not set
-- the installer when generating wgSecretKey and the upgrade key