WiX/MSI setup project

- create MinionMSI WiX project
- create MinionEXE WiX bundle project
- create MinionConfigurationExtension extension library
- simple msbuild project to restore dependencies and build the setup
  packages.
- NSIS installer changed to allow build-time definition of
  PRODUCT_VERSION, TARGET_PLATFORM and location of buildenv/distribution
  files. The default output filename uses TARGET_PLATFORM now, which
  specifies the previous value as a default.

See README.md for more details on this project.