Update examples to newer idioms

[rpavlik]

This is the output of util/find-deprecated.sh right now:

examples/advanced/light_example.lua:2:vrjLua.appendToModelSearchPath(getScriptFilename())
    [Replace with AddAppDirectory()]
examples/5-audio/sound_example.lua:3:vrjLua.appendToModelSearchPath(getScriptFilename())
    [Replace with AddAppDirectory()]
examples/in-progress/LineDrawingApp.lua:10:dofile(vrjLua.findInModelSearchPath("Line.lua"))    [Replace with runfile()]
examples/advanced/wandsphere.lua:3:wandXform = osg.MatrixTransform()    [Consider using MatrixTransform{}]
examples/3-interaction/DrawingApp.lua:15:       local xform = osg.MatrixTransform()    [Consider using MatrixTransform{}]
examples/3-interaction/Wand-Object.lua:11:      local xform = osg.MatrixTransform()    [Consider using MatrixTransform{}]
examples/2-input/Tracking.lua:10:local xform = osg.MatrixTransform()    [Consider using MatrixTransform{}]
examples/2-input/Tracking-Extended.lua:13:  local xform = osg.MatrixTransform()    [Consider using MatrixTransform{}]
examples/in-progress/LineDrawingApp.lua:19:     local xform = osg.MatrixTransform()    [Consider using MatrixTransform{}]
examples/advanced/osgnav.lua:8:scene = osg.PositionAttitudeTransform()    [Consider using Transform{}]
examples/advanced/osgnav.lua:28:    self.navtransform = osg.PositionAttitudeTransform()    [Consider using Transform{}]
examples/advanced/osgnav-statemachine.lua:7:    navtransform = osg.PositionAttitudeTransform()    [Consider using Transform{}]
examples/3-interaction/DrawingApp.lua:45:               local newPoint = osg.PositionAttitudeTransform()    [Consider using Transform{}]
examples/advanced/osgnav.lua:14:osgnav = {position = osg.Vec3d(0, 0, 0)}    [Use Vec() instead]
examples/advanced/osgnav-statemachine.lua:22:osgnav.position = osg.Vec3d(0, 0, 0)    [Use Vec() instead]
examples/advanced/osgnav-statemachine.lua:74:   navtransform:setAttitude(osg.Quat(simplerotation.degrees, osg.Vec3d(0, 1, 0)) )    [Use Vec() instead]
examples/in-progress/shadow-1.lua:19:sm:setTextureSize(osg.Vec2s(mapres, mapres))    [Use Vecs() instead]

[rpavlik]

cc @lpberg since he's interacting with the examples.