refactor: simplify Matcher:_init ().
refactor: simplify Matcher:_init ().

* lib/specl/matchers.lua (Matcher:_init): Use clone_rename ()
instead of manual parameter merge.  Simplify accordingly.
(merge_hash): Remove.  No longer used.

Signed-off-by: Gary V. Vaughan <f9023000f29773649f3850298becb9544b5fd6a9@gnu.org>

gvvaughan/specl