Add Linux script to limit outgoing bandwidth used by Bitcoin

This commit adds a Linux script that uses tc and iptables to
limit outgoing bandwidth to Bitcoin nodes. All tcp connections with
a source or destination port of 8333 are limited to the chosen rate.
It does not alter the incoming bandwidth. Additionally, outgoing
bandwidth to a host on a local LAN (defined by the LOCALNET variable)
is not limited.
RPC: getblock(): Accept 2nd "verbose" parameter, similar to getrawtransaction, but defaulting to 1 for backward compatibility
Wallet: store key creation time. Calculate whole-wallet birthday.

This also encapsulate wallet-read state information into CWalletScanState.
Wallet: optimize rescan to skip blocks prior to birthday
Merge pull request #2747 from luke-jr/getblock_verbose0

Add verbose flag to getblock RPC so it is possible to get hex dumps of blocks
Merge pull request #2728 from runeksvendsen/master

Add Linux script to contrib/ that limits outgoing bandwidth to Bitcoin nodes
allow txindex to be removed and add a reindex dialog

- adds a reindex dialog for Bitcoin-Qt to change -txindex without the need
  to supply -reindex
- now also does a -reindex, when removing the -txindex switch
changes to thread code (directly use boost::thread)

- removes our NewThread() function an replaces remaining calls with
  boost::thread with our TraceThread template
- remove ExitThread() function
- fix THREAD_PRIORITY_ABOVE_NORMAL for non Windows OSes
Merge pull request #1863 from jgarzik/keytime

"Wallet birthdays": store key create time; calc whole-wallet birthday
Merge pull request #2553 from Diapolo/threads

changes to thread code (directly use boost::thread)
fix comment about dust logic
send tx relay flag with version
Remove broken option to skip input checking for wallet txn.
fixed: include boost header as necessary

Without this include, sometimes BOOST_VERSION was defined and sometimes
it was not, depending on which includes came before it. The result was a
random mix of sleep or sleep_for for boost versions >= 1.50.
fixed: don't use thread::sleep_for where it's known to be broken

Fixes #2690.
Merge pull request #2769 from TheBlueMatt/master

Remove broken option to skip input checking for wallet txn.
Merge pull request #2766 from theuni/fix-shutdown-deadlock

Fix shutdown deadlock, ticket #2690
Merge pull request #2648 from Diapolo/txindex

allow txindex to be removed and add a reindex dialog
Merge pull request #2763 from bitsofproof/master

Send tx relay flag with version message
Merge pull request #2760 from cozz/cozz2

fix comment about dust logic