Fix a typo in Colours.lua

Author Mere <rift@dokein.co.uk>
Author date 2013-06-26 19:04:37
Author local date 2013-06-26 20:04:37 +0100
Committer Mere <rift@dokein.co.uk>
Committer date 2013-06-26 19:04:37
Committer local date 2013-06-26 20:04:37 +0100
Commit 272feb9f0f80a383bf83680c70e4cd3ea756a638
Tree 0b175204393a3aa1a3cc5b92f2c5fd29b7cd5d66
Parent 04d030500e965a0367c7e2411f6e1b1cb661c5f8
Fix a typo in Colours.lua

Add command usage when calling a sub-command with no params, or the wrong params.