[DBAL-878] Wrong mapping type

the type should be the mapping type, and not the name of the type. This
does the difference for simple_array, as the result should be
simple_array and not simplearray
Merge pull request #1018 from chandon/master

DBAL-878 Wrong mapping type
Heavily simplified code on simple object hydrator. Code cleanup on column information cache; by reference cache variable is no longer needed and protected variable is used in a standardized way everywhere.
Added type conversion to meta column in case a type is specified (such as a foreign key or discriminator column).