Contains all of the IDL files except those in [[udkapi]]

i.e. the interfaces that are specific to the OppenOffice.org application.
An artificial (?) separation.

The reference offapi/type_reference/types.rdb, used to detect inadvertent
incompatible changes, is maintained via offapi/type_reference/update-rdb.sh (see
its usage message for details) for cases where we deliberately /do/ become
incompatible.  Old such cases are listed in
offapi/type_reference/typelibrary_history.txt, new such cases are recorded in
the git log of offapi/type_reference/types.rdb.