update makefile for support Mac OS X and update UT

update makefile for support Mac OS X and update UT.
I test and run it on Max OS X 10.6 and RHEL 6.0.
I add some UT.Please review the buffer-test carefully.
before run the Unit Test please make sure the LD_LIBRARY_PATH already
include the libnessdb.so
missing dependence of the make taget

missing dependence of the make taget
run test after build

run test after build
I add test for buffer

it's seems runs fine with int,char,char*.
but when I test long. it isn't ok.
pls help me.
add some unit test for db interface

add some unit test for db interface.
please run:
make test.

look at TEST 8/8 db_test:remove.

I invoke the remove.
after that,I invoke db_exists and db_get. I also can get the value.
Is there any defect?
delete the binaray

delete the test binaray
set LD_LIBRARY_PATH for Linux

at the Linux, test binaray should link the libnessdb.so.
update make file for Linux.

Max OS X no need this.
Merge pull request #52 from tonyw/v2.0

update makefile for support Mac OS X and update UT