seed random number generator
revert commit 001790288e12ada4bd2d4956007b4f87834d84c7 for main Makefile
make examples fail nicely when eigen3 is not available
blacklist failing/flawky integration tests
corrected typo
added some assertions and prepared custom kernels for quadratic time mmd
added constructor for using a custom kernel without features
updated unit test to use new constructor for custom kernel if no data is available
Merge pull request #957 from karlnapf/master

better handling for custom kernels for quadratic time mmd
added all three methods for null approximation to precomputed kernel test
Merge pull request #958 from karlnapf/master

extended test
Merge branch 'master' of git://github.com/shogun-toolbox/shogun