./waf configure --with-optim-MinMax

/!\ init_y_heap and init_x_heap functions causes algo to crash,
error seems to come from copy of heap...

	modified:   plugins/optim-MinMax/src/strategy/ibex_light_solver.cpp
	modified:   plugins/optim-MinMax/src/strategy/ibex_minimax_solver.cpp

	modified:   plugins/optim-MinMax/src/strategy/ibex_light_solver.cpp
	modified:   plugins/optim-MinMax/src/strategy/ibex_light_solver.h
	modified:   plugins/optim-MinMax/src/strategy/ibex_minimax_solver.cpp

objective function and constraints on x. sys_y contains constraints on x and y.
New functions added to check constraints and find feasible point.
pu variable added in x_heap_elem.

	modified:   plugins/optim-MinMax/src/strategy/ibex_light_solver.cpp
	modified:   plugins/optim-MinMax/src/strategy/ibex_light_solver.h
	modified:   plugins/optim-MinMax/src/strategy/ibex_minimax_solver.cpp
	modified:   plugins/optim-MinMax/src/strategy/ibex_minimax_solver.h
	modified:   plugins/optim-MinMax/src/tools/ibex_x_heap_elem.cpp
	modified:   plugins/optim-MinMax/src/tools/ibex_x_heap_elem.h

/!\ compilation ok but not tested!!

	modified:   src/tools/ibex_DoubleHeap.h
	modified:   src/tools/ibex_SharedHeap.h

DoubleHeap Test added from ibex 2.1.x
DoubleHeap copy test
New cost function for y_heap_elem
	modified:   plugins/optim-MinMax/src/strategy/ibex_light_solver.h
	modified:   plugins/optim-MinMax/src/tools/ibex_y_heap_elem.cpp
	modified:   plugins/optim-MinMax/src/tools/ibex_y_heap_elem.h
	modified:   src/tools/ibex_DoubleHeap.h
	modified:   src/tools/ibex_SharedHeap.h
	new file:   tests/TestDoubleHeap.cpp
	new file:   tests/TestDoubleHeap.h

minmax optim now use doubleHeap and provide a (possibly very pessimistic) lower bound.

Bug corrected when y system is null

Bug corrected: constraints on x are now taken into account

Conflicts:
	plugins/wscript

ibex_y_heap_elem: remove not necessary copy

 std::pair<IntervalVector,IntervalVector> bisect(Cell& cell);
  into  
 std::pair<Cell*,Cell*> bisect(Cell& cell);

The idea is to get all the Status and trace function for every optimizer
(such as OptimMinMax)

Bsc: add bisection of Cell with Backtacable

OptimMinMax: fix trouble with deleted cells + first test

CellDoubleHeap: fix bug with print

LightOptimMinMax: add backward on the goal function
optim_MinMAx: test 1 ok

To copy all the element, use "deepcopy"
Tests have been added and no memory leak has been found.

Conflicts:
	plugins/optim-MinMax/src/strategy/ibex_DataMinMax.cpp
	plugins/optim-MinMax/src/strategy/ibex_DataMinMax.h
	plugins/optim-MinMax/src/strategy/ibex_LightOptimMinMax.cpp
	plugins/optim-MinMax/src/strategy/ibex_OptimMinMax.cpp