Added missed include guard in QuadraticTimeMMD
Reordered includes to avoid forward declaration of KernelNormalizer happen after its complete declaration
Fixed fname leak in MLDataHDF5File_unittest.cc
Merge pull request #2187 from tklein23/fix_mldata_hdf5_leak

Fixed fname leak in MLDataHDF5File_unittest.cc
Changed travis.yml build config, so that build immediately ends if compilation failed.
Merge pull request #2192 from tklein23/abort_travis_if_compilation_fails

Changed travis.yml to not execute tests if compiling failed
Trying to speed-up travis build through "cache: apt"
Merge pull request #2193 from tklein23/enable_cache_apt_in_travis

Trying to speed-up travis build through "cache: apt"
Travis: move back test into script section
refactor install and before_install to later be able to add caching support
for compiling NLOPT, JSON, Eigen
added support for rectified linear neurons
Merge pull request #2194 from khalednasr/develop

added support for rectified linear neurons
added symmetry checks in SGMatrix and modified CCustomKernel to have lhs_equals_rhs set properly