SL Bot Day - better movement, plus IM and Friend handling

Spent the day working on our ChatbotIF interface to Second Life for a change. This sits between our Discourse chatbot engine and libsecondlife. Worked my way through a list of things we'd flagged up over the past few weeks. Improvements/new features include:

- better point to point movement by estimating travel time for each segment
- full IM handling, including routing IM via Discourse and setting the bot to decline IMs
- full friend handling, including setting the bot to decline Friend requests
- a "fidget" function when idle to play random  animations and movements
- ability to set whether to ignore or listen to objects on channel 0
- ability to control movement from Discourse so the bot can more easily show people around
- accept teleport lure's form owner

Always more to do though!

***Imported from old blog***