EJSS Earth Gravity Model with more masses

EJSS Earth Gravity Model with more masses capability.

http://weelookang.blogspot.com/2015/05/ejss-earth-gravity-model-with-more.html
author: Andrew Duffy and lookang
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_gravity03_1/gravity03_1_Simulation.xhtml
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_gravity03_1.zip
https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_src_gravity03_1.zip

remixed from
Point Charge Electric Field and Potential 2D Model written by Andrew Duffy http://www.compadre.org/osp/items/detail.cfm?ID=9412

Changes made:

1. re-created on the JavaScript format.
2. customized the gravity field lines
3. sync numbers with real world data of Earth, g=9.81 m/s^2 and phi =-6.29x10^7 J/kg