src: improve the code readability
src: added instance method 'CMatrixBlock.mula()'
test: rename the variable 'block' to 'mblock'
test: fixed mistakes
test: improve readability
src: inherits from CMatrix
src: abstract the code
src: abstract the code
readme: fixed some mistakes
test: update 'MatrixBlock.assign()' testings
src: support itself MatrixBlock
src: fixed a mistake
src: abstract code and support 'MatrixBlock' and 'CMatrixBlock'
test: update testings
src: fixed a mistake
src: suport MatrixBlock and CMatrixBlock
src: support MatrixBlock and CMatrixBlock
src: fixed mistakes
src: enable instance method 'CMatrixBlock.mula()'
src: support MatrixBlock and improve readability