also test whether alias funcs are imported correct
add a note about switch to Exporter::Tiny
explicitely name Module::Runtime as prereq
add test for RT##41494: memory leak in indexes()

improve tests for indexes() to ensure that there're no leaks
add Test::LeakTrace to recommended test reqs

additionally, use the authors perl version as recommendation for META files
prove whether leak_free_ok has been executed
apply fixes from RT#86347 (spelling)
define CvISXSUB to compile on older Perls, too
fix RT#94013 in conjunction with RT#93995

* RT#94013 fix is currently done by importing all into LMU itself as
  recommended by tobyink. Documentation about the implementations has
  been added to clarify what the implementation tags mean
* RT#93995 kindly asks for access to the export tags which are provided
  by two (undocumented) methods. Have to figure out how to support that
  in future with support soon.
prepare Makefile.PL+inc/Tumble.pm for older perls
note changes of 0.400_004
bump version to 0.400_005 for upcoming criticals
improve on implementation names and precedences
fix github.com issue LMU#3 reported by tobyinc

 Run-time dependency on Module::Runtime is not declared in Makefile.PL
hack down changes in 0.400_005
delete implementation 'sno'
try to cleanup - seems there are relics from ...

try to cleanup - seems there are relics from former builds
fix remaining relics of old implementation names
seems travis build clean - my fault
bump version to 0.400_006 for next dev release