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,
Bugfix: makefile.linux-mingw: Fix so passed CXXFLAGS/LDFLAGS work correctly
Bugfix: makefile.unix: Honour BOOST_LIB_SUFFIX on boost_unit_test_framework
Drop release times for CNode

It seems there were two mechanisms for assessing whether a CNode
was still in use: a refcount and a release timestamp. The latter
seems to have been there for a long time, as a safety mechanism.

However, this timer also keeps CNode objects alive for far longer
than necessary after disconnects, potentially opening up a DoS
window.

This commit removes the timestamp-based mechanism, and replaces
it with an assert(nRefCount >= 0), to verify that the refcounting
is indeed correctly working.
Bitcoin-Qt: update for BitcoinGUI::eventFilter()

- this allows us to use the progressbar and the label independently (if
  needed) and still prevents setStatusTip() to use them, if one of the 2
  is active
moved bitcoin.svg to correct folder (qt/res/src)

Signed-off-by: Jonas Schnelli <jonas.schnelli@include7.ch>
new windows and linux icons

- new windows .ico contains multiple resolutions up to 256px
- new testnet (green) icon
- new png icon for llinux, etc.
- new doxygen icon
- changed the assets-attribution.txt

Signed-off-by: Jonas Schnelli <jonas.schnelli@include7.ch>
qt: remove redundant wallet methods from bitcoingui

send encryptWallet/backupWallet/changePassphrase directly to walletFrame
new icons: overhaul oxygen icon (was to blurry)

Signed-off-by: Jonas Schnelli <jonas.schnelli@include7.ch>
Merge pull request #2272 from gavinandresen/getbalancefix

Fix getbalance discrepency
Merge pull request #2419 from sipa/noreltime

Drop release times for CNode
Merge pull request #2477 from jonasschnelli/new_icons

new icons for windows, linux, etc.
Merge pull request #2481 from laanwj/2013_04_cleanup

qt: remove redundant wallet methods from bitcoingui
Merge pull request #2470 from Diapolo/progressbarlabel

Bitcoin-Qt: update for BitcoinGUI::eventFilter()
Merge pull request #2243 from luke-jr/bugfix_leveldb

LevelDB build bugfix
net.cpp: Do not change primary process name from (default) to "bitcoin-start"

Discussed a bit on IRC.