Add 64-bit/32-bit installer detection ability

64-bit Installer can detect the 32-bit installation (and vice versa),
and suggest users to remove the existing one before install the new one.
It works only when the existing installation is on "C:\Program Files
(x86)\Notepad++" or "C:\Program Files\Notepad++" directory

PowerEditor/installer/nppSetup.nsi

@@ -39,6 +39,7 @@ SetCompressor /SOLID lzma	; This reduces installer size by approx 30~35%
 !include "nsisInclude\winVer.nsh"
 !include "nsisInclude\gobalDef.nsh"
 !include "nsisInclude\tools.nsh"
+!include "nsisInclude\uninstall.nsh"
 
 !ifdef ARCH64
 OutFile ".\build\npp.${APPVERSION}.Installer.x64.exe"
@@ -84,22 +85,41 @@ page Custom ExtraOptions
 
 !include "nsisInclude\langs.nsh"
 
+Var diffArchDir2Remove
 Function .onInit
 
 	Call preventInstallInWin9x
 		
 	!insertmacro MUI_LANGDLL_DISPLAY
 
- !ifdef ARCH64
+!ifdef ARCH64
 	${If} ${RunningX64}
 		; disable registry redirection (enable access to 64-bit portion of registry)
 		SetRegView 64
 		; change install dir 
 		StrCpy $INSTDIR "$PROGRAMFILES64\${APPNAME}"
+		
+		; check if 32-bit version has been installed if yes, ask user to remove it
+		IfFileExists $PROGRAMFILES\${APPNAME}\notepad++.exe 0 noDelete32
+		MessageBox MB_YESNO "You're installing 64-bit version. 32-bit version has been installed. Remove it?$\n(Your custom config files will be kept)" /SD IDYES IDYES doDelete32 IDNO noDelete32 ;IDYES remove
+doDelete32:
+		StrCpy $diffArchDir2Remove $PROGRAMFILES\${APPNAME}
+noDelete32:
+		
 	${Else}
 		MessageBox MB_OK "You cannot install Notepad++ 64-bit version on your 32-bit system.$\nPlease download and intall Notepad++ 32-bit version instead."
 		Abort
 	${EndIf}
+!else ; 32-bit installer
+	${If} ${RunningX64}
+		; check if 64-bit version has been installed if yes, ask user to remove it
+		IfFileExists $PROGRAMFILES64\${APPNAME}\notepad++.exe 0 noDelete64
+		MessageBox MB_YESNO "You're installing 32-bit version. 64-bit version has been installed. Remove it?$\n(Your custom config files will be kept)"  /SD IDYES IDYES doDelete64 IDNO noDelete64
+doDelete64:
+		StrCpy $diffArchDir2Remove $PROGRAMFILES64\${APPNAME}
+noDelete64:
+	${EndIf}
+
 !endif
 
 	${MementoSectionRestore}
@@ -117,6 +137,11 @@ Section -"Notepad++" mainSection
 
 	Call setPathAndOptions
 	
+	${If} $diffArchDir2Remove != ""
+		!insertmacro uninstallRegKey
+		!insertmacro uninstallDir $diffArchDir2Remove 
+	${endIf}
+
 	Call copyCommonFiles
 
 	Call removeUnstablePlugins
@@ -127,7 +152,6 @@ Section -"Notepad++" mainSection
 	
 SectionEnd
 
-!include "nsisInclude\uninstall.nsh"
 !include "nsisInclude\autoCompletion.nsh"
 !include "nsisInclude\themes.nsh"
 !include "nsisInclude\binariesComponents.nsh"
@@ -152,7 +176,6 @@ Section -FinishSection
 SectionEnd
 
 
-
 BrandingText "Don HO"
 
 ; eof

PowerEditor/installer/nsisInclude/uninstall.nsh

@@ -115,6 +115,7 @@ Section un.UserManual
 	RMDir /r "$INSTDIR\user.manual"
 SectionEnd
 
+
 Var keepUserData
 Function un.doYouReallyWantToKeepData
 	StrCpy $keepUserData "false"
@@ -125,6 +126,43 @@ removeUserData:
 FunctionEnd
 
 
+!macro uninstallRegKey
+	;Remove from registry...
+!ifdef ARCH64
+	SetRegView 32
+!else
+	SetRegView 64
+!endif
+	DeleteRegKey HKLM "${UNINSTALL_REG_KEY}"
+	;DeleteRegKey HKLM "SOFTWARE\${APPNAME}"
+	;DeleteRegKey HKLM "SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\notepad++.exe"
+!ifdef ARCH64
+	SetRegView 64
+!else
+	SetRegView 32
+!endif
+!macroend
+
+!macro uninstallDir dir2remove
+	; Delete Shortcuts
+	Delete "$SMPROGRAMS\Notepad++\Uninstall.lnk"
+	RMDir "$SMPROGRAMS\Notepad++"
+	
+	UserInfo::GetAccountType
+	Pop $1
+	StrCmp $1 "Admin" 0 +2
+		SetShellVarContext all
+	
+	Delete "$DESKTOP\Notepad++.lnk"
+	Delete "$SMPROGRAMS\Notepad++\Notepad++.lnk"
+	Delete "$SMPROGRAMS\Notepad++\readme.lnk"
+
+	
+	RMDir /r "${dir2remove}"
+	
+!macroend
+
+
 Section Uninstall
 !ifdef ARCH64
 	SetRegView 64