* a-tags.ads, a-tags.adb (Object_Specific_Data): Remove
component Num_Prim_Ops.
(Set_Num_Prim_Ops): Removed.
Remove all the assertions because all the routines of this
package are inline always.
(Get_Offset_Index): Add support to primary dispatch tables.
Move the documentation about the dispatch table to a-tags.ads
(Set_External_Tag): Removed
(Inherit_TSD): Removed.
(Interface_Data_Element, Interfaces_Array, Interface_Data): Declarations
moved to a-tags.ads
(Displace, IW_Membership, Inherit_TSD, Interface_Ancestor_Tags,
Register_Interface_Tag, Set_Offset_To_Top): Update all the occurrences
of the TSD field "Table" because this field has been renamed to
"Ifaces_Table".
(Inherit_CPP_DT): Removed.
(K_Typeinfo, K_Offset_To_Top, K_Tagged_Kind, K_Signature,
Cstring, Tag_Table, Type_Specific_Data, Dispatch_Table): These
declarations have been moved to a-tags.ads
(Check_Size): Removed.
(Expanded_Name): Updated to get access to the new field of TSD
containing the address of the expanded name.
(Get_Access_Level/Set_Access_Level): Removed.
(Get_Predefined_Prim_Op_Address): Removed.
(Set_Predefined_Prim_Op_Address): Removed.
(Get_Prim_Op_Address/Set_Prim_Op_Address): Removed.
(Get_Remotely_Callable/Set_Remotely_Callable): Removed.
(Set_Expanded_Name): Removed.
(Inherit_DT): Removed.
(Inherit_CPP_DT): Removed.
(Set_RC_Offset): Removed.
(Set_TSD): Removed.
(Base_Address): New function that displaces "this" to point to the base
of the object (that is, to point to the primary tag of the object).