Catch a potential object fetcher error

Invalid property strings (eg 'myobject[property]' rather than
'myobject[property=value]') would throw an error... this is just a quick
catch to give a nicer error message instead.
More documentation on flag command

more meta documentation woo
(fixed)
add dPlayer.item_slot mech

A quick and simple mech to change which item the player has selected. Be
warned that clients can block or disregard this.
Merge pull request #734 from mcmonkey4eva/master

Pull request for documentation and fixing and coyotes