begin moving turtle specific code from opus into turtle package

sys/apps/system/turtle.lua

@@ -1,62 +0,0 @@
-local Config = require('config')
-local UI     = require('ui')
-
-local fs     = _G.fs
-local turtle = _G.turtle
-
-if turtle then
-	local Home = require('turtle.home')
-	local values = { }
-	Config.load('gps', values.home and { values.home } or { })
-
-	local gpsTab = UI.Tab {
-		tabTitle = 'GPS',
-		labelText = UI.Text {
-			x = 3, y = 2,
-			value = 'On restart, return to this location'
-		},
-		grid = UI.Grid {
-			x = 3, ex = -3, y = 4,
-			height = 2,
-			values = values,
-			inactive = true,
-			columns = {
-				{ heading = 'x', key = 'x' },
-				{ heading = 'y', key = 'y' },
-				{ heading = 'z', key = 'z' },
-			},
-		},
-		button1 = UI.Button {
-			x = 3, y = 7,
-			text = 'Set home',
-			event = 'gps_set',
-		},
-		button2 = UI.Button {
-			ex = -3, y = 7, width = 7,
-			text = 'Clear',
-			event = 'gps_clear',
-		},
-	}
-	function gpsTab:eventHandler(event)
-		if event.type == 'gps_set' then
-			self:emit({ type = 'info_message', message = 'Determining location' })
-			self:sync()
-			if Home.set() then
-				Config.load('gps', values)
-				self.grid:setValues(values.home and { values.home } or { })
-				self.grid:draw()
-				self:emit({ type = 'success_message', message = 'Location set' })
-			else
-				self:emit({ type = 'error_message', message = 'Unable to determine location' })
-			end
-			return true
-		elseif event.type == 'gps_clear' then
-			fs.delete('usr/config/gps')
-			self.grid:setValues({ })
-			self.grid:draw()
-			return true
-		end
-	end
-
-	return gpsTab
-end