chore: Update package install instructions

chore: Update npm package badge URL

chore: update npm package badge URL

fix linter warning

add unhandle method to Mediator

Merge pull request #4 from myty:bugfix/npm-mediator-private-variable-…

…access

Mediator private member access

Merge pull request #4 from myty:bugfix/npm-mediator-private-variable-…

…access

Mediator private member access

update build script to handle the proper ref tag

update npm build script

fix linting error