Feature/fix warnings

We should be able to compile using -Wall -Wextra -Werror.

Currently the easy fixes are done, but in the Unstructured load balancer many variables are declared (and set), but not used. I assume, this is the case due to the in progress state of the method.

Other open problems are:

• unused parameters for some implementations of setAdditionalData. If these declaration have to be there we may silence them with proper annotations (for GCC: __attribute__((unused))(ref), which should be put into a compiler dependant preprocessor switch to also set this for clang etc. as well as for readability. Maybe known_unused is a good keyword)
• ignored const on function return (ALL_LB.hpp:163: const int getNVertices() { return vertices.size(); })

This branch should only be merged to refactor after !9 (merged) has been merged!.

tests/all_class_creation.cpp

@@ -66,9 +66,15 @@ BOOST_AUTO_TEST_CASE(simple) {
 
   ALL::ALL<double, double> test(method, dimension, gamma);
 
+  // comment(s.schulz): What is supposed to be checked here?
+  //                    Just the calling? Then we should make sure to also access the result
   double check_dim = test.getDimension();
   double check_gamma = test.getGamma();
 
+  // comment(s.schulz): Not sure if there is a better way than assert in the boost framework
+  assert(check_dim == dimension);
+  assert(check_gamma == gamma);
+
   int already_final;
   MPI_Finalized(&already_final);
   if (!already_final)