Add a '-q' option to pkg check.  This increasingly mis-named "quiet
mode" is more intended for scripting use than anything else, so no
progress meters and frequently work entirely silently if no errors are
encountered.
Add the new -q flag to the pkg check commandline, now we have the
capability.
Document the new -q option to pkg check
Allow running 'pkg lock -l' without specifying any packages to lock
and hence without needing privileged access to the DB.

Free some variables used when listing the locked packages

Some whitespace cleanup

This makes pkg actually behave according to the intent expressed in
issue #635
Fix a regression breaking pkg convert
Add tests for the regression
Update documentation for pkg lock now it is possible to use 'pkg lock
-l' stand-alone, and without needing privileged pkgdb access.
Merge branch 'master' of github.com:freebsd/pkg