Fixing the problem that an operation involving a mix of
two or more GEOMETRY operands did not preserve their SRIDs.
Now SRIDs are preserved by hybrid functions, subqueries, TVCs, UNIONs, VIEWs.

Incompatible change:
  An attempt to mix two different SRIDs now raises an error.

Details:

- Adding a new class Type_extra_attributes. It's a generic
  container which can store very specific data type attributes.
  For now it can store one uint32 and one const pointer attribute
  (for GEOMETRY's SRID and for ENUM/SET TYPELIB respectively).
  In the future it can grow as needed.

  Type_extra_attributes will also be reused soon to store "const Type_zone*"
  pointers for the TIMESTAMP's "WITH TIME ZONE 'tz'" attribute
  (a timestamp data type with a fixed time zone independent from @@time_zone).
  The time zone attribute will be stored in exactly the same way like
  a TYPELIB pointer is stored by ENUM/SET.

- Removing Column_definition_attributes members "interval" and "srid".
  Deriving Column_definition_attributes from the generic attribute container
  Type_extra_attributes instead.

- Adding a new class Type_typelib_attributes, to store
  the TYPELIB of the ENUM and SET data types. Deriving Field_enum from it.
  Removing the member Field_enum::typelib.

- Adding a new class Type_geom_attributes, to store
  the GEOMETRY related attributes. Deriving Field_geom from it.
  Removing the member Field_geom::srid.

- Removing virtual methods:
    Field::get_typelib()
    Type_all_attributes::get_typelib() and
    Type_all_attributes::set_typelib()
  They were very specific to TYPELIB.
  Adding more generic virtual methods instead:
  * Field::type_extra_attributes() - to get extra attributes
  * Type_all_attributes::type_extra_attributes() - to get extra attributes
  * Type_all_attributes::type_extra_attributes_addr() - to set extra attributes

- Removing Item_type_holder::enum_set_typelib. Deriving Item_type_holder
  from the generic attribute container Type_extra_attributes instead.
  This makes it possible for UNION to preserve SRID
  (in addition to preserving TYPELIB).

- Deriving Item_hybrid_func from Type_extra_attributes.
  This makes it possible for hybrid functions (e.g. CASE, COALESCE,
  LEAST, GREATEST etc) to preserve SRID.

- Deriving Item_singlerow_subselect from Type_extra_attributes and
  overriding methods:
  * Item_cache::type_extra_attributes()
  * subselect_single_select_engine::fix_length_and_dec()
  * Item_singlerow_subselect::type_extra_attributes()
  * Item_singlerow_subselect::type_extra_attributes_addr()
  This is needed to preserve SRID in subqueries and TVCs

- Cleanup: fixing the data type of members
  * Binlog_type_info::m_enum_typelib
  * Binlog_type_info::m_set_typelib
  from "TYPELIB *" to "const TYPELIB *"