Added unit test for locally linear embedding method, that checks, whether it preserves neighbors (according to https://github.com/shogun-toolbox/shogun/issues/882)
Modified unit tests makefile, so that it adds GTEST_DIR and GMOCK_DIR to include paths, when compiling unit tests - since they do include gtest and gmock files.
Merge branch 'develop' of https://github.com/shogun-toolbox/shogun into vgorbati-develop
Merge branch 'develop' of https://github.com/shogun-toolbox/shogun into vgorbati-develop
Modified unit test for Locally Linear Embedding, so that it allows 'misses' of neighbors before and after the dimensionality reduction.
Merge pull request #990 from vladislav-horbatiuk/vgorbati-develop

Added unit test for locally linear embedding method; modified unit test makefile.