Merge branch 'develop' into super_matrix
remove unnessary debug files
update git ignore
[SparseMatrix] operator* and operator*=
[SparseMatrix] default constructor

SparseMatrix( int num_rows = 0, int num_cols = 0 )
handling zero matrix
[SparseMatrixCV] constructor
remove unnecessary debug files
update gitignore
[SparseMatrixCV ] constructor with Vec3f
Dense Matrix cv::Mat mutiplications
Merge branch 'super_matrix' into develop