new testnet window .ico file

Signed-off-by: Jonas Schnelli <jonas.schnelli@include7.ch>
Require strictly-standard encodings in mempool
Made it point to 0.8.1
Merge pull request #2527 from patbr0wn/master

Fixed download error
embed bitcoin_testnet.ico in bitcoin-qt.exe (usable for shortcuts)
Merge pull request #2520 from sipa/strictmempool

Require strictly-standard encodings in mempool
Merge pull request #2519 from jonasschnelli/new_testnet_ico_file

new testnet ico file
Add comments to UNIX Makefile regarding USE_UPNP

The tri-state nature of USE_UPNP isn't immediately obvious, so paste
the explanation from doc/build-unix.txt as a comment in the makefile.
new toolbar icon for liunx/win fix #2518

On black toolbars, the new icon doesn't look very well.
Now the toolbar icon has again a transparent "B" for better style on toolbars.
Does not affect the mac client.

Signed-off-by: Jonas Schnelli <jonas.schnelli@include7.ch>
Merge pull request #2537 from jonasschnelli/toolbaricon_linux

new toolbar icon for liunx/win fix #2518
Merge pull request #2536 from jcalvinowens/makefile-clarifying-comments

Add comments to UNIX Makefile regarding USE_UPNP