Use getopt(3)
Add dry-run mode -n
No need for trailing slash here, pkg_old_load_from_path() is adding another
Check return status of pkg_old_load_from_path() and skip if failed
Support using a different pkg_add(1) dir with -d flag
Show converting message before actually processing a package
Export OPTIONS to pkg_install(1) format

Addresses:	#431
Import OPTIONS from pkg_install(1) format

Addresses:	#431
Call pkg-convert via exec(1) to avoid subshell
Use err(3) when checking for pkg_add_dbdir
Merge branch 'convert-updates'

* convert-updates:
  Use err(3) when checking for pkg_add_dbdir
  Call pkg-convert via exec(1) to avoid subshell
  Import OPTIONS from pkg_install(1) format
  Export OPTIONS to pkg_install(1) format
  Show converting message before actually processing a package
  Support using a different pkg_add(1) dir with -d flag
  Check return status of pkg_old_load_from_path() and skip if failed
  No need for trailing slash here, pkg_old_load_from_path() is adding another
  Add dry-run mode -n
  Use getopt(3)