If/How to Deprecate/Change/Remove UNO API

Discussion has been going on for years what to do with known-stale/badly designed/un-used UNO IDL types.

Random ideas:

decide on rules when published types may be removed or changed
- number of clients in OOo
- (estimated) use outside OOo project (i.e. people that don't read interface-discuss)
- how "bad" is the API - i.e. if everybody agrees it plainly sucks, remove anyway despite points above
deprecate in one feature release (add a suitable warning mechanism when using such API)
remove in the following feature release
limit impact considerations on non-ABI-dependent UNO bindings (i.e. the assumption is that c++ components break randomly anyway for every other release, so they shouldn't block API changes)

Uno/API Deprecation