Add parameter to NeedsRepair, Add /item documentation

[zbee]

Add parameter to NeedsRepair which lets the lua macro-writer decide the level at which items need repaired, versus only returning true when broken.

This way you can have gear repaired if it's broken at all, or below a certain threshold, enabling repair macros to be done between larger chunks of crafting versus your current options of stopping when gear is broken or checking if a repair needs done between every single craft.

[zbee]

Additionally, I've added documentation for the item command added in a57a9e0