Added ability to properly update environment

Improvements

• Installer can now properly update environment to let new PATH be instantly broadcasted to system without requiring a system restart or logoff.

Credits

• The code to update environment is taken from https://github.com/chocolatey/choco (Choco - The package manager for Windows). The exact file is https://github.com/chocolatey/choco/blob/master/src/chocolatey.resources/redirects/RefreshEnv.cmd.