change 'apply/remove' to 'load/unload'

After removing the distinction between 'enabled' modules and 'applied'
modules in 022e42bc, we can change the 'apply' and 'remove' subcommands,
to more intuitive 'load' and 'unload' subcommands.

Signed-off-by: Seth Jennings <sjenning@redhat.com>
Merge pull request #111 from spartacus06/change-subcommands

change 'apply/remove' to 'load/unload'