#40463 Unittests for xtarget package -- tests/test_targets.py

    1. Using standard unittest setUp/tearDown instaed of initEnv/__cleanTmpTargets.

    2. More checks in testCreateTarget()

    3. Deprecated methods:  failUnlessEqual, failUnless -> assertEqual, assertTrue
#40463 Unittests for xtarget package

    Adding tests/test_sync.py.
#40459 Adapt the xtarget package to process multiple overlays as it was done for our version of portage
#40463 Unittests for xtarget package

    Adding optional overlay config (by default '/etc/xtarget_ov.cfg').
    Adding sync test testSyncWithOV() in tests/test_sync.py
#40459 Adapt the xtarget package to process multiple overlays as it was done for our version of portage
#40463 Unittests for xtarget package

    xtarget/builder.py, class XTargetBuilder: list_profiles() has been deleted,
list_profiles_ng() is used.

    tests/test_targets.py: More unittests - testListProfilesWithOV().
#40459 Adapt the xtarget package to process multiple overlays as it was done for our version of portage

    Extra info added for '--info' action: inform if a path exists.

    xtarget/builder.py: os.path.exists() -> exists() (because of from-import)
#40459 Adapt the xtarget package to process multiple overlays as it was done for our version of portage
Trying to fix the problem with xbuilder package which was broken by deleting list_profiles().

    1. Adding multi=True argument to XTargetBuilder.list_profiles_ng() method.

    2. More tests:
testListProfiles ->
    testListProfiles_wms, testListProfiles_wms_gr_eq, testListProfiles_no_atom
+testListProfilesWithOV_wms_ambiguous
    (to test multi=False, like it was in old method)
#38696 : fix template ebuild selection at end of xmerge --sync