Bitcoin-Qt: fix copy via context-menu broken
Bitcoin-Qt: fix copy via context-menu broken

- as QClipboard::Selection isn't available on Windows ensure that the
  correct mode is called, but sill allow selection for e.g. X11
- start conversion from QCoreApplication::instance() to qApp in
  guiutil.cpp (I intend to harmonize this all over the source with my Qt5
  compatibility pull)

joroob/reddcoin,coinkeeper/2015-06-22_18-46_reddcoin,reddink/reddcoin,ahmedbodi/poscoin,ahmedbodi/poscoin,reddink/reddcoin,coinkeeper/2015-06-22_18-46_reddcoin,reddcoin-project/reddcoin,coinkeeper/2015-06-22_19-10_cannacoin,coinkeeper/2015-06-22_19-10_cannacoin,joroob/reddcoin,reddcoin-project/reddcoin,joroob/reddcoin,ahmedbodi/poscoin,reddink/reddcoin,reddcoin-project/reddcoin,Cannacoin-Project/Cannacoin,joroob/reddcoin,reddcoin-project/reddcoin,coinkeeper/2015-06-22_18-46_reddcoin,reddink/reddcoin,Cannacoin-Project/Cannacoin,Cannacoin-Project/Cannacoin,coinkeeper/2015-06-22_19-10_cannacoin,reddcoin-project/reddcoin,bmp02050/ReddcoinUpdates,reddcoin-project/reddcoin,bmp02050/ReddcoinUpdates,bmp02050/ReddcoinUpdates,reddink/reddcoin,coinkeeper/2015-06-22_19-10_cannacoin,coinkeeper/2015-06-22_18-46_reddcoin,Cannacoin-Project/Cannacoin,coinkeeper/2015-06-22_18-46_reddcoin,ahmedbodi/poscoin,bmp02050/ReddcoinUpdates,coinkeeper/2015-06-22_19-10_cannacoin,ahmedbodi/poscoin,joroob/reddcoin,bmp02050/ReddcoinUpdates,Cannacoin-Project/Cannacoin