Merge branch 'release/0.0.31' into develop
src: added micro EIGENJS_THROW_ERROR_INVALID_INDEX_ARGUMENTS
src: added instance method 'diagonal()'
test: added instance method 'diagonal()' testings
readme: added instance method 'diagonal()' api
lint: added some files for linting pass
npm: 0.0.31 -> 0.0.32
Merge branch 'release/0.0.32'