Don't load native libraries from the domain's base directory on aspnet50
Temporarily remove aspnet50 target framework
Revert "Temporarily remove aspnet50 target framework"

This reverts commit 0ece503b6d96189dfa0a71e65f39ce9dc811ea18.
Updated build.cmd
Temporarily remove aspnet50 target framework (again)

This reverts commit 638e2360e130fb2b65e3ad1b2c64f82510a9af3e.