[Qt] extend validate line edit and btc address validator

- remove btc address length from address validator
- add an optional btc address check in validated line edit that defaults
  to off and is used in GUIUtil::setupAddressWidget()
- an isAcceptable() check is added to validated line edit on focus out
  which only kicks in, when a validator is used with that widget
- remove an isAcceptable() check from sendcoinsentry.cpp
- remove obsolete attributes from ui files, which are set by calling
  GUIUtil::setupAddressWidget()
- move some more things to GUIUtil::setupAddressWidget() and remove them
  from normal code e.g. placeholder text

src/qt/guiutil.cpp

@@ -6,6 +6,7 @@
 
 #include "bitcoinaddressvalidator.h"
 #include "bitcoinunits.h"
+#include "qvalidatedlineedit.h"
 #include "walletmodel.h"
 
 #include "core.h"
@@ -72,11 +73,16 @@ QFont bitcoinAddressFont()
     return font;
 }
 
-void setupAddressWidget(QLineEdit *widget, QWidget *parent)
+void setupAddressWidget(QValidatedLineEdit *widget, QWidget *parent)
 {
-    widget->setMaxLength(BitcoinAddressValidator::MaxAddressLength);
-    widget->setValidator(new BitcoinAddressValidator(parent));
+    parent->setFocusProxy(widget);
+
     widget->setFont(bitcoinAddressFont());
+#if QT_VERSION >= 0x040700
+    widget->setPlaceholderText(QObject::tr("Enter a Bitcoin address (e.g. 1NS17iag9jJgTHD1VXjvLCEnZuQ3rJDE9L)"));
+#endif
+    widget->setValidator(new BitcoinAddressEntryValidator(parent));
+    widget->setCheckValidator(new BitcoinAddressCheckValidator(parent));
 }
 
 void setupAmountWidget(QLineEdit *widget, QWidget *parent)