some changes
	new file:   eZLib/nbproject/configs/Study.SunSysSketch.properties
	new file:   eZLib/src/eZLib/Pair.java
	modified:   eZLib/src/eZLib/Physics/Force.java
	modified:   eZLib/src/eZLib/Physics/Gravity.java
	modified:   eZLib/src/eZLib/Study/ForceSketch.java
	new file:   eZLib/src/eZLib/Study/SunSysSketch.java
	modified:   eZLib/src/eZLib/Vector.java