* a feature to control install prefix for install targets
* usable default for install-prefix on Windows
* additional named installation prefixes based on Autotools
* allow users to add named installation directories
* fix named directories <location> handling when requesting a subproject build
* examples for named installation directories
* document named install directories-related functions, make get-package-name more conveninent to users
* feature to allow staging into a location different than active install-prefix
* support for getting relative paths with stage.get-dir