Added absolute value layer, useful for implementation of siamese networks!
This commit also replaces the default caffe_fabs with MKL/non-MKL implementation of Abs.
Merge pull request #897 from ashafaei/eltwise-abs

Absolute Value layer
[example] include imports in net surgery
[example] set phase test for fully-convolutional model
Merge remote-tracking branch 'upstream/dev' into test
modified test_mvn