add heap.h header file

	new file:   heap.h
rename heap.h to uheap.h

	new file:   uheap.h
	deleted:    heap.h
implement so func

	new file:   uheap.c
	deleted:    heap.c
	deleted:    heap.h
	deleted:    uheap.c~
	modified:   uheap.h
implement function defined in uheap.h

all function has been implement.

TODO:
        1.provide unittest.
        2.document.
	modified:   uheap.c
	deleted:    heap.c
	deleted:    heap.h
	deleted:    uheap.c~
	modified:   uheap.h