refactor db stuff to use single string dsn to avoid code duplication and introduce switch_sql_queue_manager api to create transactional sql queues to aggregate a bunch of sql stmts into transactions

Fix callback method to pass column count instead of the integer representation of the row we are on.

you cant have -- inside an xml comment... we should really be testing changes like this to the config files before we push this as this wouldnt even make it past a clean install start up or reloadxml test

Abstract the sql_manager and cache_db stuff so that modules can utilize the core functionality to run their own instance of a cached SQL connection. Includes patch to fix some segs in case ODBC does not have password set or if using PGSQL support.

Initial core-pgsql support based on native libpq; FS starts and stops without errors using core-pgsql.

FS-4695 fix apple build, seems there's no pthread_setschedprio on Mac, not sure if windows has the same problem in apr/threadproc/unix/thread.c

"Safer" version of ftdm_clamp(), that swaps min/max parameters if
vmin happens to be larger than vmax, making sure the output will
always satisfy vmin <= x <= vmax.
Signed-off-by: Stefan Knoblich <stkn@openisdn.net>

Signed-off-by: Stefan Knoblich <stkn@openisdn.net>

FS-4650 please try to use an up to date gcc when doing new dev to catch build errs.  This is what I get for the one time I did not compile test