clean up query parsing code -- will be necessary for transition to prepared statement approach
add %? autodetection parameter, simplify functions such as insert() and update() to rely on it
modify WhereClause to hold off on evaluating parameters
preparseQueryParams will now receive full WhereClause object and evaluate there
merge freeResult and checkError functions back into queryHelper() since they're only used once
%t and %lt variables can be used to hold a datetime, which will be formatted to mysql standards
DB::$usenull param can be used to decide whether insert()-like commands insert NULL or empty string for NULL
new DateTime() can be used with insert-like commands, and with %? as well