Blank module and first draft of solver API.

At this point we have a skeleton of a new module (optim) which can
barely compile properly (unlike previous commit). Besides, there is a
first draft of solver and lpsolver (linear optimization solver) in this
commit.

modules/optim/test/test_main.cpp

@@ -1,3 +0,0 @@
-#include "test_precomp.hpp"
-
-CV_TEST_MAIN("cv")