Some minor changes

Some minor changes:
    Removed some forgotten references to rAthena.
    Updated script_commands.txt for an upcoming script command modification by @shennetsind ( get_revision() for get_version() ).
    Corrected a typo in is_upper script command example.
    Updated doc/sample/npc_test_skill.txt to reflect the type 3 flag.

Signed-off-by: jaBote <j@bot.e>