Add Record::create() to support creating a model's table

Uses the $vars array to derive likely DDL for CREATE TABLE statements
Accepts custom DDL as parameter 'ddl' in $vars arrays
Add msyqli_->queryToArray($query, $keyField)

Passes array to mysqli_->query(), collects rows into array
Indexes rows by specified key field, else numerically
Update Test Record example commented at bottom of Record