#3026 Improved WiX installer

[Christian List]

This is the first WiX patch on the way to making the WiX installer our default installer.
I'll apply it on bitbucket when we get the source repository settled over there.

This patch has quite a few changes in it:

1. There are lots of whitespace changes. I think these are from Visual Studio, when I edit the xml files it reformats them for me. These changes can of course be ignored.

2. Upgraded WiX from 3.5 to 3.6.
   WiX 3.7 was released recently, so I may go ahead and update to 3.7 before long.

3. Used Visual Studio 2010 as the compiler. WiX itself isn't dependent on the Visual Studio version, so we might as well use the version that's most convenient.

4. Changed a few paths in Config.wxi, they now point to where WinMergeX64.sln actually puts them.

5. Split the ShellExtension feature out into it's own ShellExtension.wxs file. The ShellExtension is most likely the component that will give us the most headache for this installer, so having it in it's own file is good.

6. Used the UtilExentension to add support for the RestartManager. This let's the installer prompt the user to have a choice between closing Windows Explorer or restarting the computer after installation.

7. Changed the shortcut registry entries to be unique. They have to be unique, otherwise there will be uninstall problems.

8. Add detection for InnoSetup installers present on the machine already, and quitly unistalling those prior to installing the WiX installer.
   This may only be needed in the 32 bit version. But I left it in there for both version for now.

9. Fixed the Windows version detection, so it now actually works.

10. Added some additional properties to the Add/Remove Programs entry, to give users a little more information.

11. Created the first inital version of a build script for the WiX setup BuildWiXInstaller.bat. It's very rudimentary right now, but at least it's there.

[Christian List]

Committed to trunk at revision 7606