small changes before mixing release

- fix testnet (generate genesis block, update merkle root, update
  checkpoints)
- change miniTips / tinyTIPS to Thousands and Millions
- add beta coin mixing support (still have to add mixer
    announcements/revokements/network testing)
- add "anonymize coins" checkbox to send coins form and update rpc
      commands to allow :mixed after addresses (see help messages for
      sendtoaddress/sendfrom/sendmany)
update version
update checkpoints, add getchainvalue command + more
also updated int64->uint64 for amounts (probably not fully complete)
and now hard forcing 500B coin limit
add mixing fee charge if anonymize coins is chosen
add rpc user system (with access to some commands), fix some int64->uint64
errors, add access control headers
still have to fix sendtoaddress to be per-user
finish up user system, fix some display problems
only have to add per-user encryption + fix sendtoaddress now
hide boost warnings (no more warnings!), update alert key, add
generatekey/createalert/signalert/sendalert admin-only commands + more
- add root (find root username) admin-only command
- fix root user detection
- add rootuser to getinfo output
- update nsis logos/icons
- fix nsis script file
- fix genbuild.sh
- rearrange code
add fixups for MSVC2012 / Qt 5.1, HAVE_BUILD_INFO by default

must run genbuild.sh before building!
update osx / unix makefiles
cleanup qt project, cleanup error messages, cleanup code, add passwd rpc
command, force rpc server, fix OS X bugs

todo: make sure people can still connect as a client
add mixer announcements (copy of alerts system, along with rpc commands),
change rpc to use contexts instead of plain usernames, make splash screen
transparent

todo:
fix selectcoins to only select coins of the logged in user (sorta done but
its buggy, ill have to restart work on this)
make sure forcing everyone as RPC server will work
per-user wallet encryption
update checkpoints
revamp user system, each user has their own wallet

todo:
fix autoencryption on the gui client
update protocol version
fix small bug with encryption
small fixes
add per-user salts, small fix for qt
update permissions
update OS X icns files (thanks MystPhysX!)
only encrypt non-main wallets, fix passwd to use user salt