LibC: Implement POSIX binary search trees

I used RB tree for this. The implementation is based on the code on
wikipedia about RB trees.

userspace/libraries/LibC/CMakeLists.txt

@@ -32,6 +32,7 @@ set(LIBC_SOURCES
 	regex.cpp
 	scanf_impl.cpp
 	sched.cpp
+	search.cpp
 	semaphore.cpp
 	setjmp.cpp
 	signal.cpp