deprecated_profile_check: show eselect command
Disable IUSE check for binary pkg API consumers.

In the use() IUSE QA check, exempt binary packages for API consumers
like Entropy which do not require a full profile with IUSE_IMPLICIT and
stuff (see bug #456830).
_add_pkg: fix existing_node early return

This fixes a case where it would return early, before calling
_add_slot_operator_dep, which could prevent slot-operator backtracking
from working properly. This makes SlotChangeWithoutRevBumpTestCase work
properly when we add an undesirable app-arch/libarchive-3.1.1 binary
package.
_slot_operator_update_probe: detect insignificant

This avoids rebuilding of two packages due to a sub-slot change in the
child package without revision bump. The sub-slot change is considered
insignificant until one of its parent packages needs to be rebuilt.
Add test case for bug #456340.

The problem here results from poor handling of the unsatisfied built
slot operator dep inside _add_dep, where it aborts the graph and tries
to backtrack immediately. We really want it to queue a rebuild here,
and continue filling out the graph.
Backtrack unsatisfied slot-operator, bug #456340.
SlotOperatorUnsolvedTestCase: add unwanted binpkg
_get_dep_chain: include repo names