Improve header compatibility and
code quality.
JIRA issue: CORE-19268
- Improve <imm.h> and <immdev.h>
compatibility by correctly choosing
the items.
- Use <immdev.h> instead of
<ddk/immdev.h>.
- Move INPUTCONTEXTDX, IMEINFOEX,
IMEDPI, and CLIENTIMC into
<imm32_undoc.h>.
- Adapt to these changes.