Resolve "hashtable or hash-table"
Closes #22
Makes in-hash-table
and in-hashtable
synonymous. To avoid duplicating the bodies of the clauses I introduced a macro that just sets the word to be used. I've cloned all the existing tests for hash-tables so both forms are tested; all the units pass, except six, unrelated to hash-tables, that didn't pass in the freshly clone repo before I made these changes. I've also updated the doc to cite both forms.