- FIND_PROGRAM (signtool) will now get a hint about location of signtool.exe (Windows SDK)
- Targets "package" or "msi" will now fail, l if signing is requested but does not work
  (e.g invalid certificate)
- During install, do not re-sign binaries, if they are already signed.
- Preserve mysqld_error.h timestamp whenever possible. This helps avoiding situations 
where the whole server is rebuilt, whenever comp_err.exe changes (for example after code 
signing, or also after a minor fix in mysys)
- Fix Wix error in UpgradeVersion, if patch part of the version is 0.