fix some cosmetic glitches in the codebase

- rename URL into URI in paymentserver where correct
- add some missing Qt-coding-stuff in paymentserver
- change QSpinBox to QLineEdit as base for BitcoinAmountField in .ui files
  (as this is the result when converting the BAF back into base)
- remove some c_str() and replace with QString::fromStdString()
- remove several new-lines
- remove unneeded spaces
- indentation fixes

src/init.cpp

@@ -778,7 +778,7 @@ bool AppInit2(boost::thread_group& threadGroup)
 
                 uiInterface.InitMessage(_("Verifying blocks..."));
                 if (!VerifyDB(GetArg("-checklevel", 3),
-                              GetArg( "-checkblocks", 288))) {
+                              GetArg("-checkblocks", 288))) {
                     strLoadError = _("Corrupted block database detected");
                     break;
                 }