XOR error on master branch

[Nazgull09]

GHC version 7.10.3 Start to build XOR example and it fails with:

==> XOR predictions: 
xor: different dimensions 1 and 2 in dot product

[NCrashed]

Reproduced on ghc-8.1 with call stack:

[ncrashed@localhost LambdaNet]$ xor
==> XOR predictions: 
xor: different dimensions 1 and 2 in dot product
CallStack (from HasCallStack):
  error, called at src/Internal/Numeric.hs:674:19 in hmatrix-0.18.0.0-Fz3aWszNafKEHfpiQQ3J1E:Internal.Numeric
  udot, called at src/Internal/Container.hs:191:11 in hmatrix-0.18.0.0-Fz3aWszNafKEHfpiQQ3J1E:Internal.Container
  dot, called at ./AI/Trainer/BackpropTrainer.hs:61:30 in LambdaNet-0.2.0.0-FueNqgQ7xpzAKbfh2PWxoJ:AI.Trainer.BackpropTrainer
  updateLayer, called at ./AI/Trainer/BackpropTrainer.hs:53:30 in LambdaNet-0.2.0.0-FueNqgQ7xpzAKbfh2PWxoJ:AI.Trainer.BackpropTrainer
  calculateNablas, called at ./AI/Trainer/BackpropTrainer.hs:41:39 in LambdaNet-0.2.0.0-FueNqgQ7xpzAKbfh2PWxoJ:AI.Trainer.BackpropTrainer
  backprop, called at ./AI/Trainer/BackpropTrainer.hs:34:31 in LambdaNet-0.2.0.0-FueNqgQ7xpzAKbfh2PWxoJ:AI.Trainer.BackpropTrainer
  fit, called at ./AI/Trainer.hs:127:22 in LambdaNet-0.2.0.0-FueNqgQ7xpzAKbfh2PWxoJ:AI.Trainer
  trainUntil, called at ./AI/Trainer.hs:108:3 in LambdaNet-0.2.0.0-FueNqgQ7xpzAKbfh2PWxoJ:AI.Trainer
  trainNTimes, called at examples/XOR.hs:30:12 in main:Main