Portability: Constants are Bitwised

• Portability mode constants are bitwised.
• Can combine them using | and remove them using ^.
• Turn on all portability options:
  $db->setOption('portability', DB_PORTABILITY_ALL);
• Enable lowercasing and trimming:
  $db->setOption('portability', DB_PORTABILITY_LOWERCASE | DB_PORTABILITY_RTRIM);
• Enable all options except trimming:
  $db->setOption('portability', DB_PORTABILITY_ALL ^ DB_PORTABILITY_RTRIM);