Fix EncryptKeys crash introduced by a9ba4710, identified by TD.

Fixes issue #424

Bugfix: don't overuse limited ExtractAddress

ExtractAddress was called with the keystore as argument in RPC and
UI, limiting results to own keys. This caused empty "address"
fields.

make SetHash160 return a value (as specified in the function signature)

keys indexed by address + introduced CBitcoinaddress

Fix for small change outputs

With the separation of CENT and MIN_TX_FEE, it is now reasonable
to create change outputs between 0.01 and 0.0005, as these are
spendable according to the policy, even though they require a fee
to be paid.

Also, when enough fee was already present, everything can go into
a change output, without further increasing the fee.

Actually use mapAlreadyAskedFor.

Previously, mapAlreadyAskedFor was read from, but never added to.
The original intent was to use mapAlreadyAskedFor to keep track
of the time an item was requested and "Each retry is 2 minutes
after the last".
This implements that intent.

Cbitcoinaddress

Fix typo in CBase58Data::CompareTo

Updated German translation

Error in Russian Translation

Split off features unrelated to addresses from CBitcoinAddress to
CBase58Data, so they can be reused.

Instead of conversion functions between pubkey/uint160/address in
base58.h, have a fully fledged class CBitcoinAddress (CAddress was
already taken) to represent addresses.

Make CKeyStore's interface work on uint160's instead of pubkeys, so
no separate global mapPubKeys is necessary anymore.

Update makefile.vc for wallet encryptions.

added polish wallet encryption messages

Fix bad return values in LoadWallet.

Single DB transactions

Fix Build in GetReservedKey() in wallet.cpp

Generate Warning when using default key.

Cuts disk activity at startup immensely

Fix crashes when a wallet is locked and GetReservedKey() is called

Warning fixes