Merge branch 'release/0.0.32' into develop
src: improve source code
src: remove redundant code
src: added instance method 'isDiagonal()'
test: added instance method 'isDiagonal()' testings
lint: added some files for linting pass
readme: added instance method 'isDiagonal()' api
npm: 0.0.32 -> 0.0.33
Merge branch 'release/0.0.33'