Cleaning the code of simplex method

In particular, the following things are done:
*) Consistent tabulation of 4 spaces is ensured
*) New function dprintf() is introduced, so now printing of the debug
information can be turned on/off via the ALEX_DEBUG macro
*) Removed solveLP_aux namespace
*) All auxiliary functions are declared as static
*) The return codes of solveLP() are encapsulated in enum.

modules/optim/doc/linear_programming.rst

@@ -0,0 +1,48 @@
+Linear Programming
+==================
+
+.. highlight:: cpp
+
+optim::solveLP
+--------------------
+Solve given (non-integer) linear programming problem using the Simplex Algorithm (Simplex Method).
+What we mean here by "linear programming problem" (or LP problem, for short) can be
+formulated as:
+
+.. math::
+    \mbox{Maximize } c\cdot x\\
+    \mbox{Subject to:}\\
+    Ax\leq b\\
+    x\geq 0
+
+Where :math:`c` is fixed *1*-by-*n* row-vector, :math:`A` is fixed *m*-by-*n* matrix, :math:`b` is fixed *m*-by-*1* column vector and
+:math:`x` is an arbitrary *n*-by-*1* column vector, which satisfies the constraints.
+
+Simplex algorithm is one of many algorithms that are designed to handle this sort of problems efficiently. Although it is not optimal in theoretical
+sense (there exist algorithms that can solve any problem written as above in polynomial type, while simplex method degenerates to exponential time
+for some special cases), it is well-studied, easy to implement and is shown to work well for real-life purposes.
+
+The particular implementation is taken almost verbatim from **Introduction to Algorithms, third edition**
+by T. H. Cormen, C. E. Leiserson, R. L. Rivest and Clifford Stein. In particular, the Bland's rule
+(`http://en.wikipedia.org/wiki/Bland%27s\_rule <http://en.wikipedia.org/wiki/Bland%27s_rule>`_) is used to prevent cycling.
+
+.. ocv:function:: int optim::solveLP(const Mat& Func, const Mat& Constr, Mat& z)
+
+    :param Func: This row-vector corresponds to :math:`c` in the LP problem formulation (see above).
+
+    :param Constr: *m*-by-*n\+1* matrix, whose rightmost column corresponds to :math:`b` in formulation above and the remaining to :math:`A`.
+
+    :param z: The solution will be returned here as a row-vector - it corresponds to (transposed) :math:`c` in the formulation above.
+
+    :return: One of the return codes:
+
+::
+
+    //!the return codes for solveLP() function
+    enum
+    {
+        SOLVELP_UNBOUNDED    = -2, //problem is unbounded (target function can achieve arbitrary high values)
+        SOLVELP_UNFEASIBLE    = -1, //problem is unfeasible (there are no points that satisfy all the constraints imposed)
+        SOLVELP_SINGLE    = 0, //there is only one maximum for target function
+        SOLVELP_MULTI    = 1 //there are multiple maxima for target function - the arbitrary one is returned
+    };