Revises and documents the confusing and inconsistent set of
dependencies for the kernel's two main public include files.
The files now now clearly exhibit the following behaviors:
1) microkernel.h provides access to all public microkernel APIs,
public nanokernel APIs (both architecture-independent and
architecture-specific ones), and public "generic kernel" APIs
(such as kernel version and system clock APIs).
2) nanokernel.h provides access to all public nanokernel APIs
(both architecture-independent and architecture-specific ones),
and public "generic kernel" APIs.
Change-Id: I64d1e88bb033ef10692033bb78e44cdcbe8124bc
Signed-off-by: Allan Stephens <allan.stephens@windriver.com>