Fix getbalance discrepency

Two changes:

Use IsConfirmed() instead of IsFinal(), so 'getbalance "*" 0' uses the same
'is this output spendable' criteria as 'getbalance'. Fixes issue #172.

And a tiny refactor to CWallet::GetBalance() (redundant call to IsFinal -- IsConfirmed
calls IsFinal).
getbalance with no arguments and 'getbalance "*" 0' could return different different results,
add address and account information to listunspent
Also copy the address to the X11 clipboard (the one you middle-click to paste)
Some unit tests for CAlert
-alertnotify=<cmd>

Runs a shell command when an AppliesToMe() alert is received.
%s in the <cmd> string is replaced with the alert.strStatusBar
message.
translations update 2013-03-19 (bitcoinstrings.cpp / bitcoin_en.ts)
blockchain -> block chain (used everywhere else)
Adding 'copy txid' to qt tx overview context menu
Recommend alertnotify
Minimal architectural changes necessary to support multiple wallets in bitcoin-qt
- This commit is a minimal restructuring necessary to support multiple wallets in the UI. Please see multiwallet-qt.txt for details.
Make MIN_TX_FEE match MIN_RELAY_TX_FEE.

Current relay behavior is widely deployed. Supplying a higher minfee than
mining and relaying just irritates users without anti-spam gain.
Fix transaction fee in uBTC

Step for buttons 'up' and 'down' - 0.001. With BTC and mBTC all ok, but
0.001 uBTC is lower than minimal value (satoshi)
User should press 10 times on 'up' button to get 0.01 uBTC
Save & restore window size and position
Show window in center of screen on first launch
(finally) Remove IRC Seed support now that lfnet is down.
Update contrib/debian (including IRC removal)
Add a new testnet dnsseed (currently only static list, will update)
Don't specify a point size for "Wallet"
Clean up global datastructures at shutdown.

This should make detecting leaks much easier.
Don't use -dbcache for BDB anymore

-dbcache was originally used to set the maximum buffer size in the
BDB environment, and was later changed to set the chainstate cache
and leveldb caches. No need to use it for BDB now that only the
wallet remains there.

This should reduce memory allocation (but not necessarily memory
usage) a bit.