Import pkg_install 20110215.

--- 20110215:
Fix audit-history subcommand to include patterns making use of [x-y] notation.

--- 20101212:
Don't warn about _ALPHA, _BETA, _PATCH, _RC, _STABLE mismatches when
pkg_add'ing on NetBSD.

--- 20101122:
Fix crash in pkg_info -X on hand-written packages.

--- 20100915:
Allow https URLs.

--- 20100914:
Add -D flag to pkg_install, to override the "pkg_add -U" check that
all depending packages have their dependencies satisfied by the new
package. Essentially, split off this particular behavior as a special
case of -f, so that -f works as before, unforced works as before, and
one can give -D to override exactly this check, leaving all other
checks intact.

The -D flag is in support of make replace, as the workflow for make
replace is that inter-package dependencies are sometimes violated (but
then one must replace the depending packages, which is what
pkg_rolling-replace does via the unsafe_depends flags).

Add missing break statement in option parsing of "pkg_add -C", riding
the version bump.