Add the ability to change the TARDIS 'desktop theme'

Command: `/tardis desktop`
Permission: `tardis.upgrade`

Not finished - need to clear old blocks when downgrading to smaller
size etc
Jettison unused blocks if downgrading to smaller TARDIS
Open upgrade GUI if SHIFT-clicking ARS sign
When downgrading reset ARS slots to stone
Remove debug statements
Link desktop theme speed to `growth.room_speed`
Add config option to set a % cost if only changing walls and floor
Tidy
Teleport player to safe location if necessary when downgrading
Display the reduced cost
Update creation help message to use Seed blocks
Update Lazarus Device to support TARDISWeepingAngels v2.0
Better entity cleanup
Oops, missed one
Try to fix TileEntity errors & set bedrock to glass so beacon works
Revert "Try to fix TileEntity errors & set bedrock to glass so beacon works"

This reverts commit 47385e16105bab444538b29c5eb809b5e4b89e54.
Set bedrock to glass so beacon works
Some consoles don't have bedrock and beacons!
Remove debug
Try fix for ticket #838

http://dev.bukkit.org/bukkit-plugins/tardis/tickets/838-odd-stacktrace/