Refactor windows installer script to accomodate further translation. Also split it up so it is easier to maintain and extend.

src/windows/options.nsi

@@ -0,0 +1,66 @@
+;Compress the header too
+!packhdr "$%TEMP%\exehead.tmp" 'upx.exe -9 --best --ultra-brute "$%TEMP%\exehead.tmp"'
+
+;Setting the compression
+SetCompressor /SOLID LZMA
+SetCompressorDictSize 64
+XPStyle on
+
+!include "MUI.nsh" 
+
+;For the file association
+!define SHCNE_ASSOCCHANGED 0x8000000
+!define SHCNF_IDLIST 0
+
+;For special folder detection
+!define CSIDL_APPDATA '0x1A' ;Application Data path
+!define CSIDL_LOCALAPPDATA '0x1C' ;Local Application Data path
+
+!define PROG_VERSION "3.0.3"
+
+; The name of the installer
+Name "qBittorrent"
+
+; The file to write
+OutFile "qbittorrent_${PROG_VERSION}_setup.exe"
+
+; The default installation directory
+InstallDir $PROGRAMFILES\qBittorrent
+
+; Registry key to check for directory (so if you install again, it will 
+; overwrite the old one automatically)
+InstallDirRegKey HKLM Software\qbittorrent InstallLocation
+
+; Request application privileges for Windows Vista
+RequestExecutionLevel admin
+
+;--------------------------------
+;General Settings
+!define MUI_ABORTWARNING
+!define MUI_HEADERIMAGE
+!define MUI_COMPONENTSPAGE_NODESC
+;!define MUI_ICON "qbittorrent.ico"
+!define MUI_LICENSEPAGE_CHECKBOX
+!define MUI_LANGDLL_ALLLANGUAGES
+
+;--------------------------------
+;Remember the unistaller/installer language
+!define MUI_LANGDLL_REGISTRY_ROOT "HKLM" 
+!define MUI_LANGDLL_REGISTRY_KEY "Software\qbittorrent" 
+!define MUI_LANGDLL_REGISTRY_VALUENAME "Installer Language"
+
+;--------------------------------
+;Installer Pages
+!insertmacro MUI_PAGE_WELCOME
+!insertmacro MUI_PAGE_LICENSE "license.txt"
+!insertmacro MUI_PAGE_COMPONENTS
+!insertmacro MUI_PAGE_DIRECTORY
+!insertmacro MUI_PAGE_INSTFILES
+
+;--------------------------------
+;Uninstaller Pages
+!insertmacro MUI_UNPAGE_CONFIRM
+!insertmacro MUI_UNPAGE_COMPONENTS
+!insertmacro MUI_UNPAGE_INSTFILES
+
+!insertmacro MUI_RESERVEFILE_LANGDLL