Implemented find/find closest for B+ tree.

Added test suite.
Fixed some b+ tree bugs.

tests/CMakeLists.txt

@@ -0,0 +1,13 @@
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/../src)
+
+find_package(Check REQUIRED)
+find_package (Threads REQUIRED)
+include_directories(${CHECK_INCLUDE_DIRS})
+link_directories(${CHECK_LIBRARY_DIRS})
+
+set(TEST_SOURCES
+        check_sdb.c
+        bplus_tree_test.c bplus_tree_test.h)
+
+add_executable(check_SDB ${TEST_SOURCES})
+target_link_libraries(check_SDB SDBLib ${CHECK_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})