src: add instance methods 'setRandom()' and 'setConstant()'
test: add instance methods 'setRandom()' and 'setConstant()' testings
test: update instance method 'setConstant()' testings
src: modify code for linting pass
lint: add some files for linting pass
readme: add instance methods 'setRandom()' and 'setConstant()' api