Cleaned up how Points getPosition works.

Added support for Pen.java to draw lines as well as points.  There is some
re-drawing of previous line segments that needs to be worked out.  I tried
to initially just draw the last two points in the touchQueue, but it
sometimes produces blank lines for the third (or fourth) touch event in a
continous line.  Not sure why yet, so at least this is visually correct.

Set the line width to a fixed 10.0f to match the point size.

touchQueue is now passed all the way down to Pen.
As I was writing the comments for the last commit, I realized that the
reason why I was getting problem with a point on the line not drawing was
because I was using a decreasingIterator.   I was originally going to do
that as a short cut to just get the last two points, but then I realized,
I may as well extract the positions of all the points since later updates
will use all the points to get a sense of acceleration etc.  When I made
that change, I used the vertexBuffer.position to get the second last point
for the line segment, but in that case, you actually need to use the
increasing Iterator.

So as a result, switch to the normal Iterator, and now only render the
last two points when drawing lines.  Also, I can drop the SDK requirement
from 9 back to 8, since I no longer need the decreasingIterator.