Point and motion

Added start screen for MotionTrackingJava and changed Projection matrix calculation. Please review this @samtstern. If you give a go ahead, Ill make similar changes to Area learning and point Cloud as well
There are many places like this were you see the same pattern.  Two `TextViews` next to each other, one with the label and one to be modified at runtime.  Instead I'd suggest doing the following:

In `strings.xml` put a format string like `<string name="position_fmt">Position: %f, %f, %f</string>`.  Then just make one text view (rather than two where one is the label).  In the activity, get the String resource from `strings.xml` and then use `String.format(formatString, posX, posY, posZ)` and `setText(...)` to set the text of the TextView.  This will reduce the number of views by 1/2.