Removed unused flat_set includes

src/storm-dft/builder/ExplicitDFTModelBuilder.h

@@ -1,6 +1,5 @@
 #pragma once
 
-#include <boost/container/flat_set.hpp>
 #include <boost/optional/optional.hpp>
 #include <stack>
 #include <unordered_set>

src/storm-dft/storage/dft/DFT.cpp

@@ -1,6 +1,5 @@
 #include "DFT.h"
 
-#include <boost/container/flat_set.hpp>
 #include <map>
 
 #include "storm/exceptions/InvalidArgumentException.h"

src/storm/builder/ExplicitModelBuilder.h

@@ -7,7 +7,6 @@
 #include <deque>
 #include <cstdint>
 #include <boost/functional/hash.hpp>
-#include <boost/container/flat_set.hpp>
 #include <boost/container/flat_map.hpp>
 #include <boost/variant.hpp>
 #include "storm/models/sparse/StandardRewardModel.h"