libstb-hal: try to clean / fix up spark build

* remove spark7162 cases, try to keep this in one machine definition
* add libstb-hal-bin package, where all binaries except pic2m2v end up
  (they are for testing only and usually not needed)
libstb-hal: make package MACHINE_ARCH
add libass recipe (spark libstb-hal needs this)
add enca recipe (libass needs this)

this is copied from project magpie's meta-magpie
add fribidi recipe (libass needs that)

this is copied from meta-openembedded/meta-oe