fixed _baseGeometry overwrite in non-animated case

Again, first time user but when running a test similar to the README file it would only display the last series of data added. Looks like when ``opts.animated`` is ``false`` the ``this._baseGeometry`` is overwritten every call to ``addData``. This removes all of the previous work done. This patch at least fixes that. Not sure if it's the best way to fix it (never used three.js before).

I should also mention that I get an error (in Firebug) when using the animated globe. It gives a few "padding 0" like console messages then errors out and never sets the size of the points:

    Error: WebGL: Drawing without vertex attrib 0 array enabled forces the browser to do expensive emulation work when running on desktop OpenGL platforms, for example on Mac. It is preferable to always draw with vertex attrib 0 array enabled, by using bindAttribLocation to bind some always-used attribute to location 0.

What browsers and operating systems do the main developers use? Just curious why I might be having more problems than other people. Or is the master branch not necessarily stable?