Started Loss, done softmax, up to p.125

I've implemented alot of support functions that needs to be refactored, optimised and tested; mean.h, exponential.h, matdiv.h matsum.h matsubtract.h. Maybe we need to have a look at if matdiv/matmul should be in the same. Same with matadd/matsubtract and if some of it should be in matvec.h.

obj/main.d

@@ -8,9 +8,12 @@ obj/main.o: src/main.cpp include/./core/omp_config.h \
  include/./numerics/inverse.h \
  include/./numerics/inverse/inverse_gauss_jordan.h \
  include/./numerics/inverse/inverse_lu.h include/./decomp/lu.h \
- include/./numerics/matmul.h include/./numerics/matvec.h \
- include/./numerics/matadd.h include/./numerics/min.h \
- include/./numerics/max.h include/./numerics/interpolation1d.h \
+ include/./numerics/matmul.h include/./numerics/matdiv.h \
+ include/./numerics/matvec.h include/./numerics/matadd.h \
+ include/./numerics/matsubtract.h include/./numerics/matsum.h \
+ include/./numerics/min.h include/./numerics/max.h \
+ include/./numerics/mean.h include/./numerics/exponential.h \
+ include/./numerics/interpolation1d.h \
  include/./numerics/interpolation1d/interpolation1d_barycentric.h \
  include/./numerics/interpolation1d/interpolation1d_base.h \
  include/./numerics/interpolation1d/interpolation1d_cubic_spline.h \
@@ -24,7 +27,9 @@ obj/main.o: src/main.cpp include/./core/omp_config.h \
  include/./modules/neural_networks/neural_networks.h \
  include/./modules/neural_networks/datasets/spiral.h \
  include/./modules/neural_networks/layers/dense_layer.h \
- include/./modules/neural_networks/activation_functions/ReLU.h
+ include/./modules/neural_networks/activation_functions/ReLU.h \
+ include/./modules/neural_networks/activation_functions/Softmax.h \
+ include/./modules/neural_networks/loss/loss.h
 include/./core/omp_config.h:
 include/./utils/utils.h:
 include/./utils/vector.h:
@@ -43,10 +48,15 @@ include/./numerics/inverse/inverse_gauss_jordan.h:
 include/./numerics/inverse/inverse_lu.h:
 include/./decomp/lu.h:
 include/./numerics/matmul.h:
+include/./numerics/matdiv.h:
 include/./numerics/matvec.h:
 include/./numerics/matadd.h:
+include/./numerics/matsubtract.h:
+include/./numerics/matsum.h:
 include/./numerics/min.h:
 include/./numerics/max.h:
+include/./numerics/mean.h:
+include/./numerics/exponential.h:
 include/./numerics/interpolation1d.h:
 include/./numerics/interpolation1d/interpolation1d_barycentric.h:
 include/./numerics/interpolation1d/interpolation1d_base.h:
@@ -65,3 +75,5 @@ include/./modules/neural_networks/neural_networks.h:
 include/./modules/neural_networks/datasets/spiral.h:
 include/./modules/neural_networks/layers/dense_layer.h:
 include/./modules/neural_networks/activation_functions/ReLU.h:
+include/./modules/neural_networks/activation_functions/Softmax.h:
+include/./modules/neural_networks/loss/loss.h: