sparse matrix unit test: add function to generator sparse matrix according to certain sparse level, fix styling to be consistent
sparse matrix unit test: add function to generator sparse matrix according to certain sparse level, fix styling to be consistent

Saurabh7/shogun,Saurabh7/shogun,lambday/shogun,Saurabh7/shogun,Saurabh7/shogun,besser82/shogun,karlnapf/shogun,sorig/shogun,karlnapf/shogun,lambday/shogun,geektoni/shogun,geektoni/shogun,sorig/shogun,karlnapf/shogun,lambday/shogun,lambday/shogun,lisitsyn/shogun,besser82/shogun,shogun-toolbox/shogun,besser82/shogun,shogun-toolbox/shogun,lisitsyn/shogun,shogun-toolbox/shogun,lisitsyn/shogun,shogun-toolbox/shogun,lambday/shogun,lisitsyn/shogun,Saurabh7/shogun,geektoni/shogun,Saurabh7/shogun,besser82/shogun,sorig/shogun,karlnapf/shogun,lisitsyn/shogun,geektoni/shogun,geektoni/shogun,besser82/shogun,lisitsyn/shogun,lambday/shogun,sorig/shogun,shogun-toolbox/shogun,Saurabh7/shogun,sorig/shogun,Saurabh7/shogun,shogun-toolbox/shogun,geektoni/shogun,karlnapf/shogun,sorig/shogun,besser82/shogun,Saurabh7/shogun,karlnapf/shogun