Win inssaller: cleanup and support for thumbnails

- remove unused file
- register DLL file to view thumbnails in Windows explorer (if the user has admin permissions)
- some code simplifications

src/WindowsInstaller/include/declarations.nsh

@@ -69,7 +69,6 @@ Var CreateFileAssociations
 Var OldVersionNumber
 Var Pointer
 Var Search
-Var SVGPath
 Var StartmenuFolder
 Var String
 Var UserList

src/WindowsInstaller/include/detection.nsh

@@ -1,46 +0,0 @@
-/*
-
-detection.nsh
-
-Detection of external component locations
-
-*/
-
-# This script contains the following functions:
-#
-# - SearchExternal, calls the functions:
-#    MissingPrograms
-#
-# - MissingPrograms, (check if third-party programs are installed), uses:
-#    SEARCH_MIKTEX
-#    SEARCH_TEXLIVE
-#
-#--------------------------
-
-Function SearchExternal
-  Call MissingPrograms
-FunctionEnd
-
-# ---------------------------------------
-
-Function MissingPrograms
-  # check if third-party programs are installed
-
- ${if} ${RunningX64}
-   SetRegView 64
-  ${endif}
-
-  # test if Inkscape is installed
-  ReadRegStr $SVGPath HKLM "SOFTWARE\Classes\inkscape.svg\DefaultIcon" ""
-  ${if} $SVGPath != ""
-   StrCpy $SVGPath $SVGPath "" 1 # remove the leading quote
-   StrCpy $SVGPath $SVGPath -14 # # delete '\inkscape.exe"'
-  ${endif}
-  ${if} $SVGPath == ""
-   # this was used before Inkscape 0.91:
-   ReadRegStr $SVGPath HKLM "Software\Microsoft\Windows\CurrentVersion\Uninstall\Inkscape" "InstallLocation"
-  ${endif}
-
-FunctionEnd
-
-# ---------------------------------------

src/WindowsInstaller/include/init.nsh

@@ -60,6 +60,7 @@ Function .onInit
   # check if it is a 64bit system
   ${if} ${RunningX64}
    SetRegView 64
+   !define LIBRARY_X64
   ${endif}
   
   # Check that FreeCAD is not currently running
@@ -149,11 +150,6 @@ Function .onInit
   ${IfNot} ${Silent}
     # Show banner while installer is intializating 
     Banner::show /NOUNLOAD "Checking system"
-  ${EndIf}
- 
-  Call SearchExternal
-  
-  ${IfNot} ${Silent}
     Banner::destroy
   ${EndIf}