add Hehe class.
add say method and call it.
add add method.
add sub method.
add mul method.
add div method.
add div operation.
add sum method.
add mod method.
add pow method.
add pow method and pow javadoc..
Merge branch 'hehe'

Conflicts:
	src/com/flyingh/demo/Hehe.java
add test2.

Conflicts:
	src/com/flyingh/demo/Pick.java
apply patch.
Revert "apply patch."

This reverts commit 6ccff357c58b998858f4e140a800657c29e9129d.
apply patch.