Fixing segfault.  Off-by-one when setting number of dimensions in StreamingSparseFeatures.
Simple refactoring: Reuse get_dimension() from SparseVector to reduce code duplication.
Simple refactoring: Reuse dense_dot()/sparse_dot() from SparseVector to reduce code duplication.
* Fixed broken unit test (number of non-zero-entries != number of dimensions).
* Reformatting and fixing of debug output.
Thanks to HeikoS: Disabling reference counting for temporary sparse vectors.
Merge pull request #1443 from tklein23/fix_streaming_sparse

Fixing segfault. Off-by-one when setting number of dimensions in StreamingSparseFeatures.