Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Add missing 'bp', since it should be passed as g_print_bio() argument.

Oked by: pjd

Better English.

Submitted by: ru

- Document two new function g_alloc_bio() and g_duplicate_bio().
- Bump modification date.
- Update copyright years.

Document BIO_FLUSH request.

- Add two fields to bio structure: 'bio_cflags' which can be used by
consumer and 'bio_pflags' which can be used by provider.
- Remove BIO_FLAG1 and BIO_FLAG2 flags. From now on new fields should be
used for internal flags.
- Update g_bio(9) manual page.
- Update some comments.
- Update GEOM_MIRROR, which was the only one using BIO_FLAGs.

Idea from: phk
Reviewed by: phk

Tiny markup fixes.

Sort SEE ALSO references (in dictionary order, ignoring case).

Spelling fixes.

These hyphens don't need to be escaped.

Pointed out by: pjd@

Update several GEOM related manual pages:

*) Fix spelling errors.
*) Better english.
*) Re-phrasing.

Not Reviewed by: pjd (one week timeout)
Approved by: grog (mentor)

Add reference to the g_access(9) manual page.

Document g_print_bio() function.

Approved by: scottl (mentor)

Added first part of GEOM kernel API manuals pages.
Documented function and macros are:
- DECLARE_GEOM_CLASS(),
- g_attach(),
- g_detach(),
- g_new_bio(),
- g_clone_bio(),
- g_destroy_bio(),
- g_new_consumer(),
- g_destroy_consumer(),
- g_read_data(),
- g_write_data(),
- g_post_event(),
- g_waitfor_event(),
- g_cancel_event(),
- g_new_geomf(),
- g_destroy_geom(),
- g_new_providerf(),
- g_destroy_provider(),
- g_error_provider(),
- g_provider_by_name(),
- g_wither_geom().
and more to come.

I want to thanks following people for help with those documents:
Slawek Zak <zaks@prioris.mini.pw.edu.pl>
Simon L. Nielsen <simon@FreeBSD.org>
Pieter de Boer <g.p.de.boer@st.hanze.nl>
and of course
Poul-Henning Kamp <phk@FreeBSD.org>

Reviewed by: phk, scottl
Approved by: phk, scottl (mentor)