LGPL for compressed sparse matrix code from CSparse

[rwl]

Some of the compressed sparse matrix method implementations seem to have been translated directly from CSparse. E.g:

https://github.com/rwl/ParallelColt/blob/master/src/main/java/cern/colt/matrix/tdouble/impl/SparseRCDoubleMatrix2D.java#L710

https://github.com/rwl/CSparseJ/blob/master/src/main/java/edu/emory/mathcs/csparsej/tdouble/Dcs_dupl.java#L44

CSparse is distributed under the LGPL. The LGPL is not so permissive as the CERN license under which the cern.colt.matrix.* packages are provided.