Windows: Cleanup build scripts; no include\afs or include\rx

Windows: Cleanup build scripts; no include\afs or include\rx

As part of the build system cleanup, minimize the number of
directories in which include\afs and include\rx paths are included
by default.  To acheive this goal the windows openafs dirent.h is
moved from include\afs to include, references whenever possible to
openafs headers included in include\afs or include\rx are prefixed
with afs\ or rx\ as appropriate.

Some source files or directories have a broad range of interdependencies
that make separation quite challenging.  For those directories or files
the inclusion of the path is added at the smallest possible level.
At some point in the future the WINNT\afsd\ headers should be moved
from include\afs to include\WINNT and should be installed there first
and then referenced internally from that location instead of from the
WINNT\afsd directory.  That will permit further cleanup to be performed.

Change-Id: I5e3a9623071c71db2f4445dc43266fdb3dad2c91
Reviewed-on: http://gerrit.openafs.org/2961
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>