* Using child storage, (srml-support only), test failing .
* fix simple tests.
* Enumerable by requiring owned struct (previous form only allow
&'static).
Broken tests are from genesis init.
* implement for_child_keys_with_prefix
* indent
* clear_child_prefix fix.
* clear_child_prefix fix 2.
* fix for storage_impl, if/when allowing child and not child this could be
reverted.
* Fix lot of urlinked child genesis, still need to look upon actual
genesis srml module code.
Probably still a lot of broken code needing debugging.
* switch well_known_key to their associated module child trie.
Fix a genesis init (balance).
Complete some testing.
Comment some tests before using.
* fixing test runtime child keys
* latest commit fix broken genesis init
* fix system balances child name.
* Important fix: storage_root from test externalities need children (it is
already the case for ext).
* executive root with child calculation
* Avoid empty trie on test ext.
* Symetric removal of key for system.
* commenting changes related tests.
* Remove child module specifics.
* fix issues.
* fix some formatting
* fix bench and bump runtime
* Remove extend_storage_overlays, assimilate_storage do the same as is
proper considering srml macro.
* Fix warning for assimilate.
* Removing kill as they do not impact any test cases.
* Use tuple of storage map instead of two parameters. This changes the
behavior of decl_storage genesis build closure (breaking api).
* Do not use build storage before assimilate.
* fix error
* Update core/state-machine/src/backend.rs
cheme