optenv32 template support

[Cyanoxygen]

This PR does the following major things:

• Split lib/default.sh into several files, which allows some of the pre-definitions to be overridden, e.g. predefined standard installation paths.
• move and rename i386 to optenv32, and sync the build flags with amd64 one.
• Allows packages to specify ABHOST=optenv32, which then runs the configure step with linux32, and other optenv32-specific changes.
• Make changes to build templates to support optenv32.
• Add a filter to automatically remove the arch.-independent files.
• Deploy override files after running the filters