fix bug. add test. add makefile

fix bug:
        insert element bug
        remove element bug
        __uheap_parent bug
add test:
        require CUnit lib.use 'make test' to test.
add makefile:
        use 'make' to compile and 'make install' to install.
        (note: 'make install' require root permission)

TODO:
        write sample.
        document.
	new file:   Makefile
	new file:   testcase.c
	modified:   uheap.c
	modified:   uheap.h