MDL-24116 removing old xmldb test suite, all tests are now in DB function tests - improved coding style

MDL-24080 new $notlike parameter added to our new sql_like(), hopefully nobody started using the $escaped param yet; unittests  included

MDL-23925, MDL-23888 new sql_ilike() and sql_binary_equal() - this should finally allow us to solve many collation issues consistently for all supported databases; please note this changes some behaviour for non-english languages when mysql used; expect more commits that actually make use of these new features

MDL-23568 parameters of DML function insert_record are not modified any more < improved coding style, now using cast to array consistently

mysql and postgres to perform central normalisation of values for insert/
update/set_field. Now all DB drivers cast empty strings to 0 when working
with numeric columns (integer and decimal)

MDL-20700 coding style cleanup - cvs keywords removed, closign php tag removed, trailing whitespace cleanup

MDL-19474 One year and a half ago we started designing and implementing our new databse abstraction layer which included brand new moodle native drivers. Today we are finally removing old legacy drivers that were still using adodb internally. From now on the adodb will be used only in some authentication and enrolment plugins, we are probably going to drop adodb there too later in 2.x. Thanks everybody who helped test and improve our new drivers, even bigger thanks to all the great developers who created ADOdb!