Make devel_query_table() reusable

Problem/Motivation

devel_query_table() does a beautiful job of formatting the query log, and offering "placeholder / argument / EXPLAIN" links. Unfortunately it cannot be called more than once per page, because the request ID is stored in the global Drupal.settings variable.

Being able to reuse this function would be super useful for fine-grained performance metrics, especially in light of DBTNG's Database::getLog function (which can capture more than one log simultaneously). An example would be logging the queries run inside a particular panel pane.

Proposed resolution

Only a very small change is needed - the request ID is stored as a DOM attribute, instead of a global variable.

Remaining tasks

Patch needs review.

User interface changes

N/A

API changes

N/A