Merge branch 'release/0.0.54' into develop
src: add instance method 'norm()'
test: add instance method 'norm()'  testings
readme: add instance method 'norm()' api
lint: add some files for linting pass
npm: 0.0.54 -> 0.0.55
src: abstract the code
test: improve instance method 'norm()' testings
readme: improve instance method 'norm()'
Merge branch 'release/0.0.55'