FL-1246: Fork dev-lang/tcl, dev-lang/tk and media-gfx/brlcad

- Stabilizes dev-lang/tcl-8.6.1, dev-lang/tk-8.6.1 and media-gfx/brlcad-7.18-4
- Fixes build failure with media-gfx/brlcad-7.18-4
- Adds media-gfx/brlcad-7.24.2
FL-1436: Fork dev-lang/ruby

- Stabilizes dev-lang/ruby-1.9.3-p547, 2.0.0-p481 and 2.1.2